Poland on Wednesday said the missile that killed two people in the country appeared to have come from Ukraine's air defense systems, and not from Russia.
The blast in Poland on Tuesday happened close to Ukraine's border came amid a broader Russian barrage of missiles at sites across Ukraine, raising the prospect that one had missed its target.
But Poland's president said on Wednesday that he did not believe that was what happened, per The Wall Street Journal.
Andrzej Duda tweeted that there were many signs the missile had actually come from Ukraine's air defense systems and had "unfortunately" fallen on Polish territory.
Duda said there was no indication that it was a deliberate attack on Poland or that the missile was fired by Russia, but said the missile was most likely Russian-made.
US President Joe Biden also said that information so far suggests the missile may have been from Ukraine.
He said that after a roundtable with G20 leaders on Wednesday morning "I don't want to say that until we completely investigate it but it is unlikely in the lines of the trajectory that it was fired from Russia — but we'll see."
Three US officials also suggested to the AP that the missile came from Ukraine, citing early intelligence assessments and speaking on the condition of anonymity.
A source told Reuters the same theory, saying that Biden told G7 and NATO allies that a Ukrainian air-defense missile was to blame.
The strike being from Russia could have dire consequences: as a NATO state, Poland can rely on other countries including the US to come to its aid, including potentially declaring war.
But Poland and Ukraine are allies, meaning the reaction will likely be different if the missile came from Ukraine.
Jakub Orzechowski/Agencja Wyborcza.pl via REUTERS
Other nations and alliances steered clear of reaching a firm conclusion earlier on Wednesday.
Leaders of the UK, France, and Germany urged against jumping to conclusions.
NATO confirmed the strike on Poland and the deaths, and is holding an emergency meeting on Wednesday. It has not commented on the missile's origin.
Russia has denied any involvement, and also said that Ukrainian systems were to blame.
Ukraine blamed Russia on Tuesday, but a an advisor to Ukraine's defense ministry was more restrained when talking to CNBC on Wednesday.
He said it was a "very sensitive" issue and noted world leaders were being deliberately cautious: "It is too early to give any definitive answers and it's very dangerous to jump to any conclusions."