Police say they have arrested a third suspect over an explosion last month at a Sikh temple in the German city of Essen.

Police said the male suspect was arrested in Essen on Wednesday evening but gave no further details. They said in a statement that investigators are still working to clear up "the events and structures" behind the bombing.

Three people were wounded in the blast April 16, one of them seriously. Regional officials have said that the two 16-year-old suspects already arrested sympathized with the Islamic State group and one of them had been in a violence prevention program aimed at Islamic extremists.

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