The U.S. Africa Command says it has sent a joint team with the Niger military to the village of Tongo Tongo to investigate the Oct. 4 attack by extremists that left four American and four Nigerien soldiers dead.
AFRICOM said Sunday that the on-site investigation is part of a wider review across the U.S., Africa and Europe and by multiple agencies to determine how the attack took place.
The U.S. command team is interviewing residents around Tonga Tonga, visiting relevant areas and retracing steps taken before the ambush.
The Pentagon has said its investigation won't be finished until at least January.
Questions have arisen over whether the soldiers' commando unit was carrying out its assigned mission when it was ambushed about 200 kilometers (120 miles) north of Niamey.