The Bucharest Nine or the Bucharest Format (B9 or B-9; , ), or NATO's Eastern Flank (ambiguous as of 2025) is an organization founded on 4 November 2015 in Bucharest, Romania, at the initiative of the president of Romania Klaus Iohannis and the president of Poland Andrzej Duda during a bilateral meeting between them. Its members are Bulgaria, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Romania and Slovakia. Due to its separate history, Finland is not a member despite its location and its NATO membership since 2023.
Its appearance was mainly a result of perceived aggressive attitude from Russia following the annexation of Crimea from Ukraine and its posterior intervention in eastern Ukraine both in 2014. All members of the B9 were either part of the former Soviet Union (USSR) or members of the defunct Soviet-led Warsaw Pact. All members are also members of NATO and members of EU.
History Since its foundation on 4 November 2015, the Bucharest Nine countries have held several meetings at various levels. A tabular list follows the historical development.
In June 2018, prior to the B9 meeting that year, President of Poland Andrzej Duda spoke out in favour of Ukrainian and Georgian NATO membership ambitions.
On 10 May 2021, during a B9 video conference summit which the president of the United States Joe Biden joined, President of Romania Klaus Iohannis (one of the two hosts of the summit, the other being Duda) called for "stronger allied military presence [...] on the bloc's eastern flank" following the mobilization of Russian troops near the Russian border with Ukraine which had happened some time before.
On 25 February 2022, the B9 group with the addition of Ursula von der Leyen, President of the European Commission, gathered in light of the 2022 Russian invasion of Ukraine.
The 10 June 2022 B9 summit was attended virtually by the secretary general of NATO, Jens Stoltenberg, as well as the presidents of the Czech Republic and Slovakia. On it, Duda declared "We want the enhanced forward presence that we have today on NATO's eastern flank to be extended. We want the existing battalion groups to be transformed into brigade groups." Duda added that a brigade group has 3,000 troops, which would mean a "significant and visible strengthening", while Iohannis said that "NATO must be capable to defend every inch of its territory". Iohannis added that the B9 summit agreed in favour of admitting Finland and Sweden into NATO and told participants of the meeting that "security risks to Romania and the Black Sea region are increasing", and in the press release it was written that the meeting was in order to prepare for the most important decisions of NATO's 2022 Madrid summit. Furthermore, the president of Estonia Alar Karis stated during the meeting that all nine members agree that Russia is a threat to NATO.
On 11 October 2022, the B9 presidents, along with the presidents of North Macedonia and Montenegro, condemned and demanded the end of that month's series of Russian missile strikes on Ukrainian civilian targets and described them as war crimes to be punished under international law.
At a summit on 22 February 2023, the heads of state of the Bucharest Nine countries, as well as Biden and Stoltenberg, signed a declaration which issued a condemnation of the Russian invasion of Ukraine and called for an enhanced military presence of NATO on the eastern flank of the alliance.
On 2 June 2025, leaders of the Bucharest Nine and Nordic countries pledged to work toward gradually increasing defence spending to at least 5% of their gross domestic product in response to mounting security threats, particularly from Russia. The commitment was made in a joint statement issued following a summit in Vilnius, co-chaired by Lithuanian president Gitanas Nausėda, Polish president Andrzej Duda, and Romanian president Nicușor Dan. The international meeting was also attended by NATO secretary general Mark Rutte and Ukrainian president Volodymyr Zelenskyy.Bucharest Nine, Nordic leaders pledge to boost military spending to 5% at Vilnius summit
Summits Summits of heads of state
+ B9 summits of heads of state Year Date Country City Host leader Ref. 2015 4 November Bucharest Klaus Iohannis 2018 8 June Warsaw Andrzej Duda 2019 28 February Košice Andrej Kiska 2021 10 May Bucharest Klaus Iohannis and Andrzej Duda 2022 25 February Warsaw Andrzej Duda 2022 10 June Bucharest Klaus Iohannis and Andrzej Duda 2023 22 February Warsaw Andrzej Duda, Klaus Iohannis and Zuzana Čaputová 2023 6 June Bratislava Zuzana Čaputová, Andrzej Duda and Klaus Iohannis 2024 11 June Riga Edgars Rinkēvičs 2025 2 June Vilnius Gitanas Nausėda, Nicușor Dan and Andrzej Duda 202613 MayBucharestNicușor Dan and Karol Nawrocki
Summits of ministers of foreign affairs + B9 meetings of foreign affairs ministers Year Date Country City Ref. 2016 8 November Bucharest 2017 9 October Warsaw 2020 10 March Vilnius 2021 27 October Tallinn 2022 31 March Bratislava 2023 31 March Łódź 2024 26 May Brussels
Summits of ministers of defence + B9 meetings of defence ministers Year Date Country City Ref. 2018 12–14 March Bucharest 2019 4 April Warsaw 2021 25 November Bucharest 2022 6 June Videoconference 2023 26 April Warsaw 2024 19 September Bucharest
See also European Union Intermarium NATO Enhanced Forward Presence Three Seas Initiative Visegrád Group Nordic-Baltic Eight
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