OSW Commentary

A multi-speed mobilisation. NATO’s eastern flank one year after the Russian invasion of Ukraine

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The Russian invasion of Ukraine has challenged the security of the countries of NATO's eastern flank on an unprecedented scale. The Baltic states, the Visegrad Group and the Black Sea states are all situated in the neighbourhood of Ukraine or Russia. Due to the invasion, the sense of threat posed by Russia has escalated significantly, although Russia had already been seen as a threat in the region since at least the annexation of Crimea in 2014. All these countries are advocates of strengthening NATO’s collective defence and allied presence on the eastern flank. Most of them are among the top contributors to the political and military support provided to Ukraine. Defence policy and the modernisation of the armed forces have clearly gained priority throughout the region.[1]

As regards defence, Poland’s partners on the eastern flank have responded to the Russian invasion of Ukraine in different ways. Not all of them decided to significantly step up military spending in the first year of the war, and the process of modernisation of the armed forces is proceeding at different paces. In most of these countries, there is political consensus about security policy and treating Russia as a threat. However, the approach of Bulgaria and Slovakia might change due to upcoming parliamentary elections in both of these countries. Hungary has adopted a clearly different policy than the rest of the countries on NATO’s eastern flank, as it is continuing cooperation with Russia and has not provided military support to Ukraine.

The Baltic three: stepping up defence

The Baltic states have acknowledged Russia as a real threat since at least 2014. The invasion of Ukraine has only made this perception keener. Lithuania, Latvia and Estonia are among the countries which have offered the greatest share of their GDP to support Ukraine. Military spending in these countries reflects the sense of growing threat. Lithuania and Latvia began allocating 2% of GDP annually to defence in 2018, and Estonia had already begun in 2015. As a result of the Russian invasion of Ukraine, the governments of the Baltic states decided to step up defence spending at a faster rate. Estonia is planning to allocate as much as 2.9% of GDP for military purposes already this year. Lithuania increased its defence spending in the middle of last year to 2.52% of GDP. According to the 2023 preliminary budget, this level will be maintained. Latvia plans to spend 2.25% of GDP on defence this year and 2.5% by 2025. In the long run, all the three countries are planning to reach the level of 3% of GDP. Lithuania, Latvia and Estonia see NATO as the main guarantor of their security.

The development of artillery, air defence and military infrastructure is the top priority in the process of the modernisation of the armed forces in all three Baltic states. The existing training grounds and barracks are insufficient for the needs resulting from the presence and exercises of allied forces. The war in Ukraine has demonstrated the critical role of artillery, so the three countries are currently acquiring this. Estonia ordered 12 more Korean K9 howitzers (bringing the total number to 36), and Lithuania acquired 18 French CAESAR howitzers to add to the 21 German PzH 2000 howitzers it already owns. Furthermore, all three Baltic states have submitted requests for proposal to the US in order to acquire a total of 20 HIMARS multiple rocket launchers. So far, Lithuania and Estonia have signed contracts, for eight and six launchers respectively. Although the purchases are formally carried out separately, they are an effect of tripartite consultations. All the Baltic states are also acquiring very short-range air defence. Estonia and, most likely, Lithuania purchased the Polish Piorun man-portable air defence systems, while Latvia acquired the Swedish RBS 70 NG system. In June 2022, the defence ministers of Latvia and Estonia signed a letter of intent on joint purchases in the area of short-range air defence, and Lithuania is in talks to acquire more NASAMS batteries.

In addition to all these measures, Lithuania and Latvia are strengthening the potential of their land forces. After the Russian invasion of Ukraine, Lithuania embarked on negotiations to purchase 120 more German Boxer/Vilkas wheeled infantry fighting vehicles (it already has 88 of them). In addition, it has already purchased about 500 American JLTV armoured off-road vehicles. In turn, Latvia, as part of industrial cooperation with Finland, ordered over 200 Patria 6x6 wheeled armoured personnel carriers in 2021. Delivery and commissioning began in 2021 and will last until 2029.[2] Latvia is set to sign a contract for Norwegian NSM anti-ship coastal defence missiles in 2023. In addition, in 2022, Riga also decided to reinstate conscription as one of the options in the process of reintroducing the compulsory national defence service (mandatory military service has been in force in Lithuania since 2015 and has always applied in Estonia).[3] In turn, Tallinn has been focusing, in addition to the priorities listed above, on modernising soldiers’ personal equipment and weapons and plans to increase the number of conscripts as part of mandatory military service.

Lithuania, Latvia and Estonia have been making efforts to increase the NATO presence in the Baltic region for years. Estonia has been developing special military relations with the United Kingdom and France. Lithuania has been investing in building stronger bonds with Germany. For Latvia, Canada is the closest partner. All three countries treat developing military relations with the USA as a priority. Since 2017, reinforced multinational battalion-size battlegroups (of over 1,000 soldiers) have been operating in Lithuania, Latvia and Estonia. The strength of these formations has been slightly reinforced since the beginning of the Russian invasion of Ukraine. During NATO’s 2022 Madrid summit, a compromise formula was found regarding how to assign a standby force to individual Baltic states, which could be rapidly deployed there from the framework nation countries, if needed. These forces, together with a permanent rotational presence, would form an individual brigade for each of the Baltic states. This formula has not satisfied the Baltic states, which are seeking to increase a permanent NATO rotational presence in their territory. For the time being, they are in dialogue with the framework nations of NATO battlegroups (Germany, Canada and the United Kingdom) in the 3+3 format, which is intended to align the adopted solutions and enhance co-operation between NATO battlegroups.[4]

The divided Visegrad Group

The Russian invasion of Ukraine has entrenched the negative perception of Russia in the Czech Republic and Slovakia. However, this perception is also partly an effect of centre-right parties coming to power: in Slovakia in 2020 and in the Czech Republic in 2021. Both countries are currently among the top contributors of political and military support for Ukraine. However, the perception of Russia as a threat is more deeply rooted in the Czech Republic. The position of the government (which was reinforced after the presidential election in January this year) is strongly supported by both the Czech political elite and most of the Czech public. The situation is different in Slovakia, where a significant part of the population traditionally have a positive attitude towards Russia.[5] After the early parliamentary election planned for September, the pro-Atlanticist course may weaken, and initiatives to support Ukraine may be scaled down in Slovakia. Hungary, on the other hand, does not see Russia as a threat to its security, although at the same time it stresses that NATO is a pillar of its national security. Budapest has taken the most restrained stance on the Russian invasion and has not provided Ukraine with military support. Hungary wants a ceasefire to be announced and peace talks to start as soon as possible. This would let it continue its policy of balancing between East and West, which is becoming increasingly difficult in the current situation.

For years, the Czech Republic has had one of the lowest levels of defence spending among NATO member states. The country allocated 1.33% of GDP on defence in 2022, and for most of the last decade its spending in this sector hovered around 1% of GDP. According to recent declarations, its defence spending will reach 2% of GDP in 2024, i.e. one year earlier than in the pre-invasion plans. It is expected that this goal will be easier to achieve, given the plans to make public procurement rules more flexible. The country has embarked upon modernising its armed forces and is close to achieving another NATO goal: allocating at least 20% of defence spending on buying new equipment. Slovakia is already meeting the targets set by NATO in terms of both the defence spending level (2% of GDP in 2022) and the share of expenditure on modernisation of the army (26%). This is also linked to the gradual repayment of the price remaining to be paid for equipment ordered by the previous government, primarily F-16 fighters. Hungary has not changed its defence spending as a result of the Russian invasion of Ukraine, and is continuing its pre-war plan to step this up. Hungary for years spent about 1% of GDP on defence, but its defence budget has been gradually increasing since 2015 (in 2022 it reached $3 billion, i.e. 1.6% of GDP). The Hungarian Ministry of Defence has promised it will reach the level of 2% of GDP in 2023. However, Budapest may find it difficult to achieve this goal due to economic problems, including the plunging national currency, the highest inflation in the EU and a high level of debt.

The Russian invasion of Ukraine made the Czech Republic and Slovakia step up the modernisation of their land forces. The coordinated acquisition of Swedish CV90 infantry fighting vehicles is a priority for both countries (the Czech Republic wants to buy 210 vehicles and Slovakia 152). They are also receiving and deploying used German Leopard 2A4 tanks (the Czech Republic 14 and Slovakia 15). The two countries received the tanks to backfill after their military support for Ukraine. The Czech Republic and Slovakia are likely to buy 30 to 60 new Leopard 2A7 tanks each as part of a joint coordinated purchase. In 2022, Slovakia signed an agreement on the acquisition of 78 Finnish AMV Patria XP 8x8 wheeled armoured personnel carriers. The Slovak armed forces will also be gradually modernised due to successive deliveries of equipment purchased under contracts concluded before the Russian invasion of Ukraine. The land forces will receive, among other supplies, 25 Zuzana 2 self-propelled guns manufactured in Slovakia (most of them have already been delivered to the army). The Czech Republic is also implementing modernisation projects which were launched before 2022. 68 Pandur II wheeled armoured personnel carriers and, as part of industrial cooperation with France’s Nexter (ten more howitzers were ordered in December 2022), 52 CAESAR howitzers will be acquired. The Czech Republic and Slovakia are also investing in their air forces. Bratislava ordered 14 new F-16 aircraft; the first units will be delivered in 2024. Prague, on the other hand, is negotiating the acquisition of 24 F-35A aircraft with the US. It would like to introduce them starting from 2027 in place of the 14 leased JAS-39 Gripen fighters. Earlier, Slovakia purchased 17 3D radars (contract signed in 2021 with Israel) and two Black Hawk UH-60M helicopters (contract signed in 2021; the army already has nine of these). Hungary has been implementing a decade-long programme for the modernisation of its entire armed forces since 2016. These plans have not been modified since the Russian invasion. The main partners in this process are German arms companies, mainly Rheinmetall, which has opened or plans to open a total of four production plants in Hungary. In 2022, the country received the first of 218 Lynx infantry fighting vehicles and two of 24 PzH 2000 self-propelled guns. Deliveries of 44 Leopard 2A7+ tanks are to begin in 2024. In recent years, Budapest has purchased 20 H145M light helicopters, and 16 H225M medium helicopters are set to be delivered in 2023. Hungary will also receive US-Norwegian NASAMS 3 air defence systems in 2023.

In March 2022, following the Russian invasion of Ukraine, NATO decided to create four multinational battalion battle groups in the remaining four countries of the eastern flank, including Slovakia and Hungary (in addition to Romania and Bulgaria). The Czech Republic does not see itself as an eastern flank country in the exact meaning of the term as it borders only NATO member states and non-allied Austria; it has thus not sought an allied military presence. Instead, it has become the framework nation of a small battalion battle group in Slovakia, which also includes soldiers from the Netherlands, Germany and Slovenia. This move has reinforced Slovakia’s air defence with three batteries of Patriot medium-range air defence systems. Bratislava is also enhancing bilateral military cooperation with Germany, which has deployed two batteries in Slovakia, and will soon send two MANTIS very short-range artillery air defence systems to protect the plants that repair German PzH 2000 howitzers, which are used in Ukraine. Polish and Czech fighters are patrolling the Slovak airspace since the last 11 Slovak MiG-29 fighters were grounded in 2022 and the F-16 aircraft have not yet been put into service. In turn, the battalion group in Hungary is only nominally an allied formation. Its core consists of Hungarian units reinforced with an American company and soldiers from other countries, including Croatia. Hungary (unlike Poland, Romania, the Czech Republic and Slovakia) has not decided to send its soldiers to battle groups in other countries on the eastern flank. The Hungarian Air Force took part in a rotation of the Baltic Air Policing mission in 2022.

Romanian concerns and Bulgarian caution

Romania believes that Russia poses a major threat to both Romania and the entire Black Sea region, including the Republic of Moldova (especially since the annexation of Crimea in 2014). Romania and Moldova share a cultural and historical heritage as they used to be part of the same state in the past. Therefore, a special position is reserved for Moldova in Bucharest’s foreign policy. The war has escalated Romania’s concerns and mobilised it to enhance cooperation with NATO and the US, and to intensify efforts to strengthen the presence of NATO troops on its territory and in the Black Sea. Romania feared that its strategic situation could be strongly affected if the Russian offensive in Ukraine turned out to be successful. In the worst case scenario, which the Romanian government considered likely at the beginning of the war, Russian troops could be deployed next to the Romanian border and even enter Moldova.[6] For a long time, Bulgaria did not treat Russia as a security threat, considering its close economic (especially in the energy sector) and cultural relations with Moscow, as well as the awareness of Bulgaria’s low military potential. Its approach was modified to some extent only after Russia had annexed Crimea in 2014. No fundamental changes were noticed in Sofia’s cautious policy after the Russian invasion of Ukraine in 2022. Nevertheless, Bulgaria unofficially did offer significant support to Kyiv (including supplies of ammunition and fuel), especially in the first months of the war.[7] The Bulgarian political elite is divided over the response to the Russian aggression. Some pro-Atlanticist parties argue that Bulgaria should modernise its armed forces and offer military support for Ukraine. Other parties prefer neutrality and some are outright pro-Russian.

The difference in the perceptions of security threats is also reflected in defence spending. Romania intends to increase its military expenses in 2023 from 2% to 2.5% of GDP (approximately €7.9 billion). In 2022, Bucharest expanded its defence budget by 18% to a record-high level of around €5.3 billion. In 2024-2026, it is expected to grow further by 7.5-8% annually and reach around €10 billion, i.e. almost double that of 2022. The annexation of Crimea in 2014 mobilised successive Bulgarian governments to embark upon military reforms in 2015-2020 and to gradually increase defence spending to 2% of GDP in 2018-2024. The Russian attack on Ukraine did not make Bulgaria modify these plans to a significant extent or change the value of its defence budget in 2022. The budget was approximately €920 million (1.73% of GDP), i.e. only slightly higher than in 2021.

Romania was continuously postponing and prolonging programmes aimed at modernising its armed forces. These programmes have been streamlined since the Russian invasion of Ukraine. Tactical aviation and air defence remain the main priorities. Bucharest wants to equip its armed forces with a total of seven batteries of the Patriot medium-range air defence system; four of them have already been ordered and one was delivered in 2020. A tender was also launched for the purchase of man-portable air-defence systems and electronic warfare systems. The Romanian government has also made efforts to step up the acquisition of 32 used F-16 aircraft from the Norwegian Air Force; the first of them will be delivered to Romania at the end of 2023. In 2022, Romania ordered various types of unmanned systems and two H215M helicopters. In January 2023, it concluded a contract for the supply of two batteries of Norwegian NSM anti-ship coastal defence missiles. In contrast, Bulgaria, is not modernising its armed forces on a large scale due to a shortage of funds. In November 2022, the government and parliament approved the purchase of eight more F-16 fighters (there will be a total of 16 of them, the first batch was ordered in 2019, deliveries are to start in 2025). The purchase of 150 wheeled armoured personnel carriers and the replacement of the old-generation air defence systems dating back to the Warsaw Pact era, remains unresolved.

Romania has been making efforts for years to ensure a strengthened presence of NATO forces on its territory and the deployment of NATO battlegroups in the Black Sea region, similar to those operating in the Baltic states. Bulgaria has not been a particularly active participant in the discussions regarding this issue. Romania achieved its goal in the first half of 2022, after NATO decided in March 2022 to create four additional battalions, including two in the region. France is the framework nation of the battle group in Romania (about 1,100 soldiers). At the same time, the United States has increased its military presence in Romania to about 4,000 soldiers. According to information provided by the Romanian government in November 2022, about 5,000 soldiers from NATO countries were stationed in the country, which means a tripling of the allied presence. In turn, the creation of a NATO battlegroup of 1,000 soldiers has been the most visible reinforcement of Bulgaria’s security since the Russian invasion. Italy, which sent a larger contingent, became the framework nation. However, Albania, Greece, Turkey and the USA also contributed to enhancing Bulgaria’s national security.


The invasion of Ukraine has made it clear to the vast majority of the countries on NATO’s eastern flank that they were right to see Russia as a threat to the region’s security. In some countries, such as Estonia, Lithuania, Latvia, the Czech Republic and Romania, there is political consensus that Moscow’s aggressive actions need to be counteracted. In others (Bulgaria, Slovakia and Hungary), a section of the political elite favours a more conciliatory approach to Russia. Regardless of how strong the sense of threat is in each of these countries, they all opt for strengthening NATO’s collective defence and NATO's presence on the eastern flank as part of both NATO and regional cooperation formats.

Most of the eastern flank countries analysed have given clear political support to Ukraine. They are among the world’s top contributors of military aid to Ukraine in terms of GDP share (Poland, the Baltic states, the Czech Republic and Slovakia). Hungary is the only country to have maintained high-level diplomatic contacts with Russia, to have continued close economic cooperation with Russia, to have refused to provide military support to Ukraine and to criticise the Western policy towards the war (however, in the end, even Hungary usually agrees to the imposition of further packages of EU sanctions and endorses official NATO documents).

Defence spending in most of the region’s countries has been gradually increasing since the mid-2010s. However, in some of them this growth slowed down after 2020 as a consequence of economic problems caused by the pandemic. The Russian invasion of Ukraine has either re-mobilised them to increase military expenditure to 2% of GDP as per their previous schedule, or has prompted them to raise it above this ceiling (as is the case with Romania). The Baltic states are planning to reach the level of 3% of GDP in defence spending in the near future.

In recent years, the modernisation of the armed forces has been stepped up in all countries across the region. This process has gained momentum since 24 February 2022 partly due to the need to replace the post-Soviet equipment donated to Ukraine. The countries of the eastern flank are increasing investments in armoured and mechanised troops, artillery and air defence.

The Central and South-Eastern European countries, which do not have a direct border with Russia (Bulgaria, Romania, Slovakia and Hungary), seem satisfied with the fact that NATO battalion battlegroups were created on their territory in 2022. Romania was the only one to have additionally strengthened the allied presence over the past year as part of bilateral military cooperation with the USA. In turn, the Baltic states claim that the arrangements made during the Madrid summit are insufficient and expect a further strengthening of the permanent allied rotational presence in the Baltic region.


[1] The paper covers Poland’s allies in the so-called Bucharest Nine, a grouping of countries of NATO’s Eastern Flank, including: Bulgaria, the Czech Republic, Estonia, Latvia, Lithuania, Romania, Slovakia.

[2] P. Szymański, Latvia’s new armour: Finnish vehicles for the Latvian Armed Forces, OSW, 4 November 2021, osw.waw.pl.

[3] B. Chmielewski, Latvia to reintroduce conscription, OSW, 14 September 2022, osw.waw.pl.

[4] J. Tarociński, J. Gotkowska, Expectations versus reality: NATO brigades in the Baltic states?, OSW, 6 December 2022, osw.waw.pl.

[5] K. Dębiec, Slovakia: strategic dilemmas after the Russian invasion of Ukraine, OSW Commentary, no. 445, 10 May 2022, osw.waw.pl.

[6] K. Całus, Extremely cautious. Romania’s approach to the Russian invasion of Ukraine, OSW, 14 October 2022, osw.waw.pl.

[7] Ł. Kobeszko, Bułgaria wobec agresji na Ukrainę, OSW, 15 April 2022, osw.waw.pl.