Kyiv and Warsaw will continue cooperating openly as closest friends, Ukrainian Foreign Minister Dmytro Kuleba said on Twitter.
On Tuesday evening, Polish authorities reported that a missile fell in the village of Przewodow.
On Wednesday, US military officials said initial findings suggested that the missile was fired by Ukrainian forces at an incoming Russian missile.
Earlier, US President Joe Biden also said it was "unlikely" that the missile, which killed two people in NATO-ally Poland, was fired from Russia.
NATO summoned an extraordinary meeting on Wednesday to decide on further steps.
The Russian Defense Ministry said it did not carry out strikes farther than 35 kilometers (about 22 miles) to the Polish border.
Polish President Andrzej Duda said there was currently no clear evidence on which side launched the missile into Polish territory.
Source: Anadolu Agency