U.S. officials believe the attack was carried out by the Iranian-backed Kata'ib Hezbollah.
One U.S. official said multiple strikes targeted Kataib Hezbollah weapons facilities inside Iraq.
The U.S. and Britain vowed to hold accountable those responsible for an attack in Iraq that killed three troops.
US official says 3 dead, including 2 US troops, and at least 10 wounded in rocket attack in Taji, Iraq.
Gunnery Sgt. Diego D. Pongo of Simi Valley, California, and Capt. Moises A. Navas of Germantown, Maryland, died Sunday.
It's the first deadly hostile incident for U.S. service members this year in the fight against ISIS in Iraq and Syria.
The size of the Iranian missiles is to blame for the increased number of troops diagnosed with TBI, a Pentagon official said.
The attack came just before 3:30 a.m. local time and caused only minor damage.
The plan is for NATO to take on some personnel and training activities now run by the US-led multinational coalition.
Esper is looking for ways to reduce the U.S. troop presence in Iraq so that some can be brought home.