Updated

A 29-year-old Tunisian man suspected of planning an attack was taken into custody after what are believed to be toxic substances were found in his apartment, prosecutors said Wednesday.

Authorities raided the man's apartment in the Chorweiler neighborhood of the western city of Cologne late Tuesday and detained him on suspicions of preparing an act of violence, prosecutors said. He was not identified due to the ongoing investigation.

Police confiscated substances thought to be toxic in his apartment and they were being evaluated by experts to determine exactly what they are. Prosecutors would not comment on the amount of substances seized.

It is not yet clear whether the case has any links to terrorism and the man has not yet been formally charged.