National Police in the Lviv region said in a statement that vandals destroyed a stone cross in Huta Penyatska that commemorated Polish villagers who were massacred in 1944 by a Nazi unit mostly composed of Ukrainian volunteers.
Up to 900 people are believed to have been killed in the village, according to the Polish Institute of National Remembrance, The Gazette reports.
The monument was erected in 2005.
Footage on Ukrainian media showed the toppled cross and two stone slabs bearing the names of the victims painted over with the colors of the Ukrainian flag and the colors of Ukrainian nationals.
Lviv police are investigating.
Poland on Tuesday sent a note to Ukraine’s foreign ministry demanding that the incident be investigated and the perpetrators punished, Poland Foreign Ministry spokeswoman Joanna Wajda told The Associated Press. Ukraine authorities assured neighboring ally Poland they were treating the case very seriously, Wajda said.
Poland’s ambassador to Ukraine, Jan Pieklo, said local authorities want to help repair the monument. Pieklo is planning to attend ceremonies marking the 73rd anniversary of the massacre next month.