A hail of rockets landed on a military base housing U.S. and other coalition troops north of Baghdad Saturday morning, wounding three coalition soldiers and two Iraqi soldiers.
The same base, Camp Taji, was the target of a rocket attack on Wednesday which killed three servicemen, including two Americans and one British.
Operation Inherent Resolve spokesman Col. Myles B. Caggins III said via Twitter that 25 missiles landed at 10:41 a.m. local time Saturday (3:51 a.m. ET).
The attack was unusual because it occurred during the day. Previous assaults on military bases housing U.S. troops typically occurred at night.
Chief Pentagon Spokesman Jonathan Hoffman referred the press to a comment made by Defense Sec. Mark Esper last week after Wednesday's rocket attack: "You cannot attack and wound American Service Members and get away with it, we will hold them to account," he said at the time.
"The Iraqi Security Forces have made an initial arrest and we are investigating the attack with them," Hoffman added. "These rocket attacks are a deadly and dangerous distraction from the coalition's mission to help the Iraqis with their goal to permanently defeat ISIS."
Wednesday's attack prompted American airstrikes Friday against what U.S. 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, while wounding five fighters from the Popular Mobilization Forces, an umbrella organization including an array of militias, including some Iran-backed groups.
Iran-backed Shiite militia groups vowed to exact revenge for Friday's U.S. strikes, signaling another cycle of tit-for-tat violence between Washington and Tehran that could play out inside Iraq.
America's killing of Iraqi security forces might also give Iran-backed militia groups more reason to stage counterattacks against U.S. troops in Iraq, analysts said.
“We can’t forget that the PMF is a recognized entity within the Iraqi security forces; they aren’t isolated from the security forces and often are co-located on the same bases or use the same facilities,” said Sajad Jiyad, a researcher and former managing director of the Bayan Center, a Baghdad-based think tank.
“Now the (Iran-backed) groups who supported the initial strike in Taji, who were the most outspoken, feel obliged, authorized, maybe even legitimized to respond, ostensibly to protect Iraqi sovereignty but really to keep the pressure up on Americans,” he added.
“There are no red lines anymore," Jiyad said.
Wednesday's attack on Camp Taji was the deadliest to target U.S. troops in Iraq since a late December rocket attack on an Iraqi base, which killed a U.S. contractor. That attack set in motion a series of attacks that brought Iraq to the brink of war.