2 Americans killed in Iraq during anti-ISIS mission identified as Marine Raiders

The Pentagon on Tuesday identified the two U.S. Marine Raiders killed in Iraq on Sunday during an anti-ISIS mission, a deadly reminder of the terror group's ongoing presence there.

According to the U.S.-led coalition in Baghdad, the two Marines were "killed by enemy forces while advising and accompanying Iraqi Security Forces during a mission to eliminate an ISIS terrorist stronghold in a mountainous area of north central Iraq," officials said on Monday.

Another four service members were wounded during the mission, a U.S. official told ABC News on Monday.

The Pentagon identified the Marine Raiders on Tuesday as Gunnery Sgt. Diego D. Pongo, 34, of Simi Valley, California, and Capt. Moises A. Navas, 34, of Germantown, Maryland. Both were assigned to 2nd Marine Raider Battalion, Marine Forces Special Operations Command in Camp Lejeune, North Carolina.

The incident marks the first U.S. troop combat deaths in Iraq this year.

In late December, an American contractor was killed in a rocket attack targeting a military base in northern Iraq. The Pentagon later identified an Iranian-backed militia group, Kata'ib Hizbollah, as responsible for the attack.

Marine Raider Gunnery Sergeant Scott Koppenhafer, 35, of Mancos, Colorado, was killed last August while advising Iraqi Security Forces on a planned mission in northern Ninevah province.

American troops have been training the Iraqi military in the fight against ISIS since 2015.