Washington urged Baghdad on Monday to prevent US military bases from being attacked as nationwide demonstrations continue to rock Iraq.
US Secretary of Defence, Mark Esper, spoke to Iraqi Prime Minister Adel Abdul Mahdi after a senior military official warned last week that attacks by Iranian-backed groups were pushing all sides closer to an uncontrollable escalation.
Mr Esper "expressed his concerns over the shelling of some installations and the necessity to take procedures to stop it", Mr Abdul Mahdi's office said.
Mr Abdul Mahdi told Mr Esper that "unilateral action could have negative consequences that will be difficult to control and might jeopardise Iraq's sovereignty".
He resigned last month under pressure from mass anti-government protests and is leading in a caretaker capacity until political leaders choose his successor.
Mr Abdul Mahdi's resignation followed nationwide protests fuelled by anger over political corruption and Iran’s influence in Iraqi politics, as well as the government’s violent response to the protesters demands.
More than 400 people have been killed and tens of thousands injured in the unrest, the UN said.
The Iraqi High Commission for Human Rights called on the government to ensure its security forces halt their “dangerous escalation against the demonstrators”.
This includes kidnapping, threatening and targeting protesters and activists.
Arshad Salihi, the head of the parliamentary human rights committee, said the government was responsible for protecting protesters.
“Abductions, assassinations and enforced disappearances against the protesters violates the principles of human rights,” Mr Salihi said.
A supporter of the anti-government protests died of gunshot wounds on Sunday morning, police said.
Mohammed Al Doujaili, 24, was shot in the back near Baghdad's Tahrir Square, which has been a centre for the protests, on Saturday night.
Another man with him was wounded in the attack.
Mr Al Doujaili was the fourth protester to be killed by unidentified assailants over the past two weeks.
Amnesty International on Friday urged Baghdad to clamp down on what it called a "campaign of terror" against protesters.