Iraq's parliament on Sunday urged the government to oust thousands of American troops from the country, stepping up pressure over the US killing of a top Iranian general in Baghdad.
US installations were also facing new military stresses, with missiles slamming into the Baghdad enclave where the US embassy is located and an airbase north of the capital housing American troops.
Ties have deteriorated after an American precision drone strike on the Baghdad international airport on Friday that killed Iran's Major General Qasem Soleimani and top Iraqi military figure Abu Mahdi al-Muhandis.
Iraq's foreign ministry summoned the US ambassador, while caretaker premier Adel Abdel Mahdi attended an extraordinary parliamentary session to slam the strike as a "political assassination".
He joined 168 lawmakers - just enough for quorum in Iraq's 329-seat parliament - to discuss the ouster of US troops.
Some 5 200 US soldiers are stationed across Iraqi bases to support local troops preventing a resurgence of the Islamic State jihadist group.
They are deployed as part of the broader international coalition, invited by the Iraqi government in 2014 to help fight ISIS.
"The parliament has voted to commit the Iraqi government to cancel its request to the international coalition for help to fight ISIS," speaker Mohammed Halbusi announced.
The cabinet would have to approve any decision but the premier had earlier indicated support for an ouster.
"We face two main choices," he told MPs: either immediately voting for foreign troops to leave or revisiting their mandate through a parliamentary process.
Hardline parliamentarians with ties to the Hashed al-Shaabi military force, which is close to Iran, had demanded a tougher decision calling for the immediate expulsion of all foreign troops.
No Kurdish and most Sunni MPs boycotted the session as they were more supportive of a US troop presence, seen as a counterweight to Iran.
They had been threatened by Hashed-linked MPs, who said they would be seen as having "betrayed" Iraq if they boycotted.
Tom Warrick, a former US official and current fellow at the Atlantic Council, said Soleimani and pro-Iran factions within the Hashed had long sought the US's ouster.
"If US forces do end up withdrawing, it could grant Soleimani a post-humous victory," Warrick told AFP.
As the session got under way, the US-led coalition announced it was suspending its Iraq operations due to deadly rocket attacks on their bases.
"This has limited our capacity to conduct training with partners and to support their operations against Daesh (ISIS) and we have therefore paused these activities, subject to continuous review," it said.
There had been fears of a volley of rocket attacks following a warning from a hardline Hashed faction for Iraqis to move away from US forces by Sunday afternoon.
Already, increased tensions prompted NATO to suspend its training activities in Iraq and a US defence official told AFP American-led coalition forces would "limit" operations.
Iraq's foreign ministry said it had summoned US ambassador Matthew Tueller to condemn American strikes on Iraq.
"They were a blatant violation of Iraqi sovereignty," the ministry said in a statement, and "contradict the agreed-upon missions of the international coalition."
The ministry also said it submitted complaints to the United Nations Security Council over the strikes, asking it to condemn Soleimani's death as an "assassination."
The US strike on Baghdad international airport early Friday killed five Iranian Revolutionary Guards and five members of Iraq's Hashed.
After a procession that made its way across various Iraqi cities on Saturday, the remains of the Iranians, plus those of Muhandis and another Hashed member, were flown to Iran.
DNA testing was required to separate the Iraqis' remains so they could be properly buried, the Hashed said.
As head of the Quds Force, the Guards' foreign operations arm, Soleimani oversaw Iran's wide-ranging interventions in regional power struggles.
In Iraq, protesters taking to the streets since October had blamed him for propping up a government they see as corrupt and inept.
'Promise of severe revenge'
Demonstrations still rocked the capital and south on Sunday, with many protest chants shifting to condemn a possible regional conflict.
US President Donald Trump claimed Soleimani was planning an "imminent" attack on US personnel in the region and threatened Iran on Saturday with more strikes.
Iran's supreme leader Ayatollah Ali Khamenei promised "severe revenge" for the death of Soleimani, who was mourned by huge crowds in Iran on Sunday.
Comments from both the US and Iran have fanned fears of an uncontrollable escalation as world powers scramble to ease tensions.
The European Union invited Iranian foreign minister Mohammad Javad Zarif to Brussels while Britain urged Iran "do the right thing" by keeping calm.