Ukrainian experts are already working at the site in the border area of southeastern Poland where a missile killed two people, Ukrainian Foreign Minister Dmytro Kuleba said on Friday.

He wrote on Twitter that Ukraine would continue “open and constructive” cooperation with Poland over Tuesday’s incident, in which two people were killed.

Warsaw and its Western allies say evidence from the scene points to the explosion being caused by a Ukrainian air defence missile that went astray in pursuit of a Russian missile. Kyiv denies this, saying it has evidence of a “Russian trace” in the blast.

“Ukrainian experts are already working at the site of the tragedy in Przewodów caused by Russian missile terror against Ukraine,” Kuleba wrote.

“I am grateful to the Polish side for granting (the experts) access. We will continue our cooperation in an open and constructive manner, as closest friends do.”