The talks in the Slovak capital by the Bucharest Nine (B9) group of NATO allies are expected to focus on efforts to strengthen the eastern flank of the Western military alliance in response to Russia's invasion of Ukraine.
Meeting participants will also discuss preparations for a NATO summit in the Lithuanian capital Vilnius next month, according to officials.
Other topics include defence spending, NATO enlargement and "hybrid threats to the security, stability and unity of the alliance," reporters were told.
President Andrzej Duda is set to represent Poland at the meeting, which will also be attended by NATO Secretary-General Jens Stoltenberg, public broadcaster Polish Radio’s IAR news agency reported.
The Bucharest Nine is a Polish-Romanian initiative launched in 2015 that aims to help exchange views and coordinate positions on the security of NATO’s eastern-flank countries.
It brings together Poland, Romania, Lithuania, Bulgaria, Estonia, the Czech Republic, Hungary, Latvia, and Slovakia.
In February, US President Joe Biden told a summit of B9 leaders in Warsaw that Article 5 of the alliance's collective defence treaty "is a sacred commitment” and that America "will defend literally every inch of NATO."
Biden was speaking in the Polish capital ahead of the one-year anniversary of Russia's invasion of neighbouring Ukraine.
Russia invaded Ukraine on February 24, 2022, launching the largest military campaign in Europe since World War II.
Tuesday is day 468 of Russia’s war on Ukraine.
Source: IAR, PAP