US President Joe Biden will join a meeting by video link of presidents of countries on NATO's eastern flank being held on Monday in the Romanian capital, according to the offices of the Romanian and Polish presidents, news wires reported. The presidents gathering represent the so-called Bucharest Nine, a group of the easternmost members of the alliance.

Most of them share a concern about Russia’s attempts to reassert its influence over their region, their anxieties growing after Russia annexed Ukraine's Crimean Peninsula in 2014, ABC noted

Romanian President Klaus Iohannis, the host, said on Twitter that he was glad to be welcoming Biden, and that the meeting was in preparation for a full NATO summit next month. He said Monday's meeting, co-hosted by Polish President Andrzej Duda, would include discussions of defense and deterrence on the alliance's Eastern flank, and that NATO Secretary General Jens Stoltenberg was also participating.

The head of Poland’s National Security Bureau, Pawel Soloch, said that security in the Black Sea region and in Ukraine would also be under discussion.

Those in the Bucharest nine are Romania, Poland, Hungary, Bulgaria, the Czech Republic, Slovakia, and the three small Baltic states of Estonia, Latvia and Lithuania. Their meeting comes ahead of a NATO summit taking place on 14 June in Brussels. At the June summit, Biden and other leaders plan to discuss tense ties with Russia and China, the troop withdrawal from Afghanistan and the future of the 30-nation alliance.