German officials say a number of Germans are traveling to Afghanistan and Pakistan for militant training, and several have returned to live in Germany.
The information comes amid reports that a U.S. missile strike in Pakistan killed five German militants near the town of Mir Ali in North Waziristan, an area known for its links to al-Qaida.
Pakistani officials say the drone strike killed at least eight militants, including five Germans.
U.S. officials believe that a cell of German and British militants are behind a recent terror plot to attack several European cities.