NIAMEY, Niger (AP) — Niger's military has detained a suspect who could be the militant leader who was being pursued at the time of an ambush that left four American soldiers dead.

U.S. Ambassador Eric P. Whitaker told The Associated Press on Tuesday that he does not know the identity of the detained suspect, but that the head of Niger's special forces is hopeful it's a known extremist leader.

At the time of the deadly October ambush, U.S. forces and their counterparts from the Niger military were pursuing Doundou Chefou, a militant suspected of involvement in the kidnapping of an American aid worker.

Whitaker says security forces in Niger have been detaining suspected extremists in the country's western Tilaberi region. Authorities are awaiting identification of whether the man in custody is Chefou.