U.S. issues security alert for Kiev --President Vladimir Putin informed his U.S. counterpart that Moscow will respond to Ukrainian attacks on Russian strategic airbases | 4 June 2025 | The U.S. embassy in Kiev has advised Americans to heed air-raid sirens and shelter appropriately, warning of "a continued risk of significant air attacks," in a new security alert issued on Wednesday. Russian President Vladimir Putin "did say, and very strongly, that he will have to respond" to recent Ukrainian attacks on airfields hosting Russian strategic bombers, U.S. President Donald Trump wrote on Truth Social on Wednesday evening, revealing details of their unannounced conversation that day. The U.S. State Department issued the security alert just hours earlier, advising Americans currently in Ukraine to "identify shelter locations in advance" and to "keep reserves of water, food, and medication."