U.S. President Joe Biden told allies that a missile that killed two people in Poland was a Ukrainian air defence missile, a NATO source said on Wednesday. Earlier, Biden said publicly that the missile was unlikely to have been fired from Russia. If confirmed, that would likely alleviate concern that the first deadly incident in a NATO country since the war in Ukraine began might lead to escalation.

NATO’s Secretary General on Wednesday later said the blast in Poland was likely caused by a Ukrainian air defence missile but that Russia was ultimately responsible because it started the war. “They are responsible for the war that has caused this situation,” Jens Stoltenberg told a news conference after an emergency meeting of NATO ambassadors. “Let me be clear this is not Ukraine’s fault.”