Croatian anti-fascists and Serb minority groups have held a commemoration ceremony at the site of a notorious World War II death camp, boycotting the official event over alleged government inaction to curb the surge of neo-Nazi sentiment in the Balkan country.

The ceremony Saturday was held a day before the Croatian government plans to mark an attempted escape in 1945 of 1,073 prisoners from the Jasenovac camp when hundreds were killed. Croatia's Jewish groups plan to hold a separate ceremony on Monday.

Croatia's Jews and Serbs were angered by the authorities' failure to remove a plaque bearing a WWII Croatian pro-Nazi salute from the town of Jasenovac. Tens of thousands of Jews, Serbs and Gypsies died in death camps run by Croatia's pro-Nazi puppet state in World War II.