Prosecutors say that an Algerian man who was allegedly tasked by the suspected ringleader of November's Paris attacks with reconnoitering the Balkan migrant route last year is in custody in Germany.

German federal prosecutors said Thursday that the 20-year-old, identified only as Bilal C. in line with German privacy rules, is accused of having been a member of the Islamic State group from December 2014 until at least last August. They said the man was already in custody over another matter.

Prosecutors say the man joined IS in Syria in 2014. They say Paris attacks suspect Abdelhamid Abaaoud tasked him last June with scouting the Balkan route that was then popular with migrants for border checks and smuggling opportunities, and that he traveled from Syria to Austria and then Germany.