WARSAW (AP) – President Joe Biden is wrapping up his whirlwind, four-day visit to Poland and Ukraine. He’s reassuring eastern flank NATO allies that his administration is highly attuned to the looming threats and other impacts spurred by the grinding Russian invasion of Ukraine. Before departing Warsaw on Wednesday, Biden will hold talks with leaders from the Bucharest Nine. The collection of nations on the most eastern flank of NATO was formed in response to Russian President Vladimir Putin’s 2014 annexation of Crimea from Ukraine. The B9 countries’ anxieties have become more heightened as many worry Putin could move to take military action against them if he’s successful in Ukraine.