Federal prosecutors say they've charged a 32-year-old German man with membership in a terrorist organization over allegations he joined the Islamic State group in Syria.

Prosecutors say that Ali R., whose last name wasn't disclosed in line with privacy laws, traveled to Syria in December 2014 to try to get his three children back from an Islamic State group-controlled area, a month after his wife took them there without his knowledge.

Once there, they said the suspect joined the group himself, serving in an administrative capacity dealing with new recruits and helping produce booby traps.

He was returning home with his children when he was arrested at Munich Airport in November 2015.

No date has yet been set for trial.