A barrage of rockets hit a base housing US and other coalition troops north of Baghdad, just days after a similar attack killed two American troops and a British soldier.
There was no immediate word on casualties at Camp Taji.
Iraq's military said that 33 Katyusha rockets had been launched on the base.
The military found seven rocket launchers and 24 unused rockets in the nearby Abu Izam area, it said in a statement, and promised to arrest those responsible.
Iraqi security officials said some rockets struck the coalition quarters while others fell on a runway used by Iraqi forces.
The Iraqi military issued a statement saying the “blatant attack” had struck Iraqi air defense units and warned the perpetrators and those who may have enabled them.
It also reaffirmed its appeal against unilateral US military action in the country.
“We also refuse that the American forces or others take any action without the approval of the Iraqi government and the commander in chief of the armed forces, as they did on the morning of 3/13/2020,” it said.
“In doing so, it does not limit these actions, but rather nurtures them, weakens the Iraqi state’s ability to provide its own security, and expects more losses for Iraqis. This necessitates the speedy implementation of the parliament’s decision on the issue of the coalition’s withdrawal,” the statement added.
The attack was unusual because it occurred during the day. Previous assaults on military bases housing US troops typically occurred overnight.
It was the 23rd such attack since late October on installations across Iraq where American troops and diplomats are based, with the latest rounds growing deadlier.
The earlier attack against Camp Taji on Wednesday prompted American airstrikes Friday against what US officials said were mainly weapons facilities belonging to Kataib Hezbollah, the Iran-backed militia group believed to be responsible.
However, Iraq's military said those airstrikes killed five security force members and a civilian.
