German prosecutors say they have arrested a man on suspicion of membership in a group that fought international and government troops in Afghanistan.

The federal prosecutor's office said Monday that the 26-year-old German citizen, identified only as Sinan Sefik A. in line with German privacy rules, was arrested after his arrival at Berlin's Tegel airport. The arrest took place on Friday and prosecutors didn't say where he had flown from.

Prosecutors accuse the man of joining the now-defunct German Taliban Mujahedeen during a trip to the Waziristan region on the Pakistan-Afghanistan border in late 2009 and early 2010. They say he was trained to fight and was involved in producing a propaganda video, but left the group in around February 2010 after clashing with other members.