The Pentagon on Friday identified the three U.S. Army Green Berets who were killed this week during what it described as an advise-and-assist mission in Niger.

The soldiers were Staff Sgts. Bryan C. Black, 35, of Puyallup, Wash.; Jeremiah W. Johnson, 39, of Springboro, Ohio; and Dustin M. Wright, 29, of Lyons, Ga., according to the announcement. All three were assigned to the 3rd Special Forces Group based at Fort Bragg, N.C.

They came under fire during a joint reconnaissance patrol with Nigerien forces in southwest Niger, which borders Mali, Chad, and Nigeria.

The U.S. has several hundred troops in the country and a drone base. It has increased its military presence in that region in recent years to counter extremist groups such as Boko Haram.

The Pentagon declined to provide many details about the mission during a press conference on Thursday.

"I don't have any further particular operational detail on this, but it's a pretty broad mission with the government of Niger in order to increase their capability to stand alone and to prosecute violent extremists in the region," Joint Staff Director Lt. Gen. Kenneth McKenzie said.