WASHINGTON (AP) — The U.S. military believes someone in a Niger village may have tipped off attackers to the presence of U.S. commandos and Nigerien forces in the area, setting in motion the ambush that killed four Americans, a senior defense official says.

The official said Tuesday that the Army Green Berets and about 30 Nigerien forces stopped in a village for an hour or two to get food and water after conducting an overnight reconnaissance mission. After they left, they were ambushed by about 50 heavily armed enemy fighters, who also killed four Nigerien fighters and wounded two Americans a...