Russian missiles have killed two people in NATO member Poland, a senior US intelligence official has told the AP news agency.
Polish Prime Minister Mateusz Morawiecki has called an urgent meeting to discuss national security, a government spokesman said on Twitter.
State news agency PAP said the meeting was to be held at 8pm GMT.
Polish media said missiles hit an area where grain was drying in Przewodow, a village in eastern Poland near the border with Ukraine.
“Firefighters are on the spot – it’s not clear what has happened,” said firefighter Lukasz Kucy.
Moscow launched a large number of missiles at Ukraine on Wednesday, knocking out power for seven million households.
It is unclear whether the two missiles that apparently landed in Poland were part of the same wave, but it is the first time Russian rockets are said to have reached Poland.
Poland has not been involved in the conflict, but has welcomed millions of Ukrainian refugees and has widely condemned the war.