Three American troops and several Iraqi forces were wounded on Saturday in the second major rocket attack in the past week on an Iraqi base north of Baghdad, US and Iraqi officials said, raising the stakes in an escalating cycle of attacks and reprisals.
Iraq's Joint Operations Command said 33 Katyusha rockets were launched near a section of the Taji base which houses US-led coalition troops. It said the military found seven rocket launchers and 24 unused rockets in the nearby Abu Izam area.
The Iraqi military said several Iraqi air defence servicemen were critically wounded. Two of the three wounded U.S. troops are seriously injured and are being treated at a military hospital in Baghdad, the Pentagon said.
Pentagon spokesman Jonathan Hoffman declined to speculate on potential responses but, in a statement, cited Defence Secretary Mark Esper's warning last week: "You cannot attack and wound American Service Members and get away with it, we will hold them to account."
An official said some rockets hit the coalition quarters, while others fell on a runway used by Iraqi forces.
Iraqi forces later discovered seven platforms from which the rockets were launched in the Abu Azam area, north of Baghdad. Another 24 missiles were discovered in place and ready to launch.
The attack was unusual because it occurred during the day. Previous assaults on military bases housing US troops typically occurred at night.
The base was also hit on Wednesday in an attack that killed three members of the international anti-ISIS coalition. Two US and one British soldier were killed in the attack that prompted retaliatory US air strikes. In the raids on several targets in Iraq, five Iraqi security forces and a civilian were killed.
The civilians killed and wounded were construction workers at an airport building site in the Shiite holy city of Karbala, Iraqi religious authorities said.
In its comments on Saturday, the Iraqi military said attacks on US troops cannot be a pretext for unilateral action without Baghdad's approval.
The Iraqi military previously said the US air strikes went against “any partnership” under the coalition to fight ISIS. “It will have consequences that subject everyone to the most serious dangers.”
On Saturday, it said the US should withdraw from Iraq, in accordance with a bill passed by parliament earlier this year.
About 5,000 US troops are in Iraq, most in an advisory capacity, as part of the international coalition formed to help Iraq drive back and defeat ISIS extremists.
The military’s comments come hours after President Barham Salih said repeated breaches could cause Iraq to unravel into a failed state and revive ISIS.
Iraq condemned Friday’s US air strikes and warned of dangerous consequences for what it called a violation of sovereignty and targeted aggression against the nation’s regular armed forces.
Iraq’s foreign ministry announced plans to bring a complaint to the United Nations and summoned the US and British ambassadors to the country for an explanation.
The ministry said on Friday that the “presence and behaviour” of US and allied forces in Iraq was to blame for attacks against them.
The US defended the air strikes, saying all five targets were legitimate and stored Iranian-supplied weapons used by the internationally sanctioned Iran-backed militia Kataib Hezbollah to attack the US-led coalition.
"These locations that we struck are clear locations of terrorist bases," said Marine Gen Kenneth McKenzie, head of the US military's Central Command.
"If Iraqis were there and if Iraqi military forces were there, I would say it's probably not a good idea to position yourself with Kataib Hezbollah in the wake of a strike that killed Americans and coalition members," he said at a Pentagon news briefing.
Gen McKenzie acknowledged that a structure had been hit near the Karbala airfield but said it was being used to store weapons.
“That was a clear target,” he said.
Iranian-backed paramilitary groups have regularly fired rockets and shells at bases in Iraq that host US forces, as well as at the area around the US Embassy in Baghdad.
Wednesday’s attack on Camp Taji was the deadliest to target US troops since a late December rocket attack on a base in northern Iraq that attack killed a US contractor, setting in motion a series of tit-for-tat strikes that brought Iraq to the brink of war.
As well as the two US and one British soldier killed in Wednesday’s attack, about 14 coalition personnel were wounded, including Americans, Britons, Poles and others. Private industry contractors were among the wounded.
London identified the soldier killed as Lance Cpl Brodie Gillon, 26, a reservist with the Scottish and North Irish Yeomanry.
It is not the first time the US has hit Kataib Hezbollah. In December they hit the group after the US contractor was killed, leading to protests at the US embassy in Baghdad.
Tension has been high since the start of the year when a US drone strike in Baghdad killed Iranian Gen Qassem Suleimani, who led expeditionary operations across the wider Middle East. Iran struck back with a ballistic missile attack on US forces in Iraq, the Islamic Republic’s most direct assault on America since the 1979 seizure of the US Embassy in Tehran.
Hours after launching the missiles, Iran shot down commercial Ukraine International Airlines flight 752 that had just left Tehran’s airport, killing all 176 aboard.
The US and Iran stepped back from further attacks after the Suleimani incident. A senior US official said in late January, when US-Iran tension had cooled, that the killing of Americans constituted a red line that could spark more violence.
Soon after Suleimani was killed, Iraq’s parliament passed a resolution calling for all foreign troops to leave the country. The most recent air strikes could see those calls renewed.
Caretaker prime minister Adel Abdul Mahdi is one of those calling for US troops to withdraw.
But Gen McKenzie said on Friday that he was confident the United States would be able to keep troops in Iraq.
He said the latest US strikes would deter militia from staging similarly deadly rocket attacks, but the risk from Iran and the groups it backs remained high.