Arsonists attacked a mosque in Poland Wednesday during the Muslim Eid al-Adha holiday amid tensions over a nationwide ban on halal animal slaughter and protests by animal rights activists.
"It was definitely arson," Grazyna Wawryniuk, spokeswoman for regional prosecuters in the Baltic port city of Gdansk where the mosque is located, told AFP.
"We have launched an investigation to determine the motives and identify the perpetrators," she said.
The fire damaged a door and part of the mosque's interior, she said.
The imam for Gdansk, Hani Hraish, told local media the attack in the early hours of Wednesday was a very rare act of violence in his community.
"Yesterday we celebrated Eid here normally. It was beautiful, joyous, we had a huge crowd and we didn't notice anything strange," he said.
"It's very unpleasant for us, very harmful. The fire didn't just burn our mosque but our heart and souls too," he added.
Poland's small Muslim and Jewish communities have come under pressure this Eid holiday to respect a January 1 ban on ritual halal and kosher slaughter after the Constitutional Court deemed it incompatible with animal rights legislation.
Animal sacrifice is part of the traditional Eid feast.
A day earlier, the country's top Muslim leader, Mufti Tomasz Miskiewicz, said his community was suffering a "witch hunt" as animal rights activists protested against halal slaughter near a small wooden mosque in the Muslim Tatar village of Bohoniki, eastern Poland.
For the first time in hundreds of years, Muslim faithful there did not perform the ritual slaughter of sheep for the annual Eid feast, under pressure from protesters to respect the ban.
Jews and Muslims in overwhelmingly Catholic Poland say the ban violates their religious freedoms and is therefore unconstitutional. The Jewish community has asked Poland's top court to rule on the matter.
Muslims also say the ban, which has spurred intense debate both at home and abroad, is invalid under European law.
European Union rules on livestock slaughter are designed to minimise animal suffering, but religious groups are exempted from a requirement that animals be stunned before death.
Under age-old kosher and halal rules, animals are killed by slitting their throats without first being stunned.
The Jewish and Muslim communities each number around 20,000 to 30,000 in Poland, an EU member state of some 38 million people.