German authorities say two teenagers suspected of carrying out a bombing on a Sikh temple in the western city of Essen were sympathizers of the Islamic State group.

Three people were wounded in the blast April 16, one of them seriously. The interior ministry of North Rhine-Westphalia state told regional lawmakers Thursday that one of the two 16-year-old suspects had been in a violence prevention program aimed at Islamic extremists.

German news agency dpa quoted a ministry spokesman saying the boy once threatened to break a Jewish fellow student's neck.

Essen police chief Frank Richter called the attack "an act of terror."