Ukrainian experts have arrived in Poland as part of an investigation to determine where a missile that killed two people was fired from, the Ukrainian foreign minister said Thursday.
"Our experts are already in Poland," said Ukraine's Foreign Minister Dmytro Kuleba on Twitter.
"We expect them to swiftly get access to the site in cooperation with Polish law enforcement."
A missile struck the Polish village of Przewodow near the Ukrainian border on Tuesday, killing two people and raising fears of an escalation in the conflict.
"Ukraine and Poland will cooperate constructively and openly on the incident caused by Russian missile terror against Ukraine," Kuleba wrote.
Ukraine President Volodymyr Zelensky said Wednesday that the missile was Russian but Kyiv's allies said the explosion was likely caused by a Ukrainian air defence missile launched to intercept Russian attacks.
Warsaw, Washington and NATO stressed that Moscow was ultimately to blame for attacking Ukraine.
The Kremlin has said it had "nothing to do with the incident".