German police say they have arrested four alleged Islamists on suspicion of illegally obtaining weapons, ahead of ceremonies Monday marking the 21th anniversary of German reunification. But authorities later said they found no evidence of plans for an attack.

Prosecutors said no weapons or other dangerous items were discovered during apartment searches in the Bonn area. Authorities also said no links to terrorist groups were established.

A police spokesman in Cologne said the suspects, ages 22 to 27, were arrested late Saturday, when police could not rule out that a crime was being prepared ahead of reunification celebrations.