This picture taken on Friday shows damaged military vehicles in Iraq’s Babylon province. AFP

Two Iraqi security officials said a barrage of rockets hit Camp Taji, the second time the base, which houses US-led coalition troops was attacked this week.

The officials spoke Saturday on condition of anonymity in line with regulations.

On Wednesday, three servicemen, including two Americans, were killed when the base was attacked, the deadliest to target US troops in Iraq since a late December rocket attack on an Iraqi base that killed a US contractor and set in motion a series of tit-for-tat attacks that brought Iraq to the brink of war.

In retaliation, the US launched a series of airstrikes on militia bases across Iraq's south, killing five Iraqi security forces and a civilian.