President Andrzej Duda on Monday pledged to fight racism and anti-Semitism 70 years after dozens of Polish Holocaust survivors were massacred in a brutal pogrom.
"It's the army and militia that opened fire first" on the Jewish inhabitants of the southern city of Kielce, Duda said during ceremonies marking the anniversary.
He described the communist police's behavior as "bestial."
There is "no justification for anti-Semitic crime", he said, vowing to fight "even the most minor of acts of racism, anti-Semitism and xenophobia."
"The problem is not only that the militia and army attacked (the Jews) but that other people joined in as well."
On July 4, 1946, Kielce erupted in a frenzy of hatred after a rumor spread that a Jewish family had held a Christian boy in a cellar overnight.
Communist police, soldiers and workers from a nearby steelworks raided a house on 7/9 Planty Street sheltering Holocaust survivors, including some from the infamous Auschwitz-Birkenau Nazi German death camp.
At least 42 Jews were killed and over 40 injured in the worst anti-Semitic attack in postwar Poland, according to the Washington-based United States Holocaust Memorial Museum.
The pogrom went down as one of the darkest moments in the 1,000-year-long history of Polish Jews.
A Polish enquiry put the Jewish death toll at 37, with other victims including three non-Jewish Poles and two people killed during a robbery.
After the violence, tens of thousands of Jews left the country.
Nine people were sentenced to death for their role in the killings, but the Communist authorities of the time tried to blame regime opponents for the crime.
AFP contributed this report.