U.S. officials say an American soldier missing for nearly two days in Niger has been found dead. He was one of four U.S. troops killed in a deadly ambush.

His body was found and identified Friday after an extensive search. Four Niger security forces were also killed.

U.S. officials say they believe extremists linked to ISIS were responsible for the attack about 200 kilometers north of Niger's capital of Niamey.

The joint patrol of U.S. and Niger forces were leaving a meeting with tribal leaders and were in trucks. They were ambushed by 40-50 militants in vehicles and on motorcycles.

Eight Niger soldiers and two U.S. troops were wounded. The officials weren't authorized to discuss the matter publicly and spoke on condition of anonymity.

The Pentagon earlier identified three of the four U.S. Army special operations commandos who were killed in Wednesday's attack.

They were 35-year-old Staff Sgt. Bryan Black, from Puyallup, Washington; 39-year-old Staff Sgt. Jeremiah Johnson, from Springboro, Ohio, and 29-year-old Staff Sgt. Dustin Wright, from Lyons, Georgia. All were from the 3rd Special Forces Group, based at Fort Bragg.

Officials have said the Green Berets were likely attacked by al Qaeda in the Islamic Maghreb militants.

In a statement announcing their deaths, U.S. Africa Command said the forces, in Niger to provide training and security assistance, were with a joint U.S. and Nigerien patrol north of Niamey, near the Mali border, when they came under hostile fire.

Black, Johnson and Wright died of wounds sustained during enemy contact, the Pentagon said. The incident is still under investigation.

