Tehran wields growing influence in Iraq, particularly through armed militias.
Since October 28, 10 rocket attacks have targeted areas where US soldiers and diplomats are stationed. The attacks have not been claimed but the US has blamed Iranian-supported paramilitary groups.
US Defense Secretary Mark Esper told reporters on Monday he expressed “concern about the optics in attacks on bases in Iraq where US troops and material might be” in a call with outgoing Prime Minister Adel Abdul Mahdi.
The US has “a right of self-defence that we would ask our Iraqi partners to take proactive actions … to get that under control, because it’s not good for anybody”, Esper told Abdul Mahdi.
Abdul Mahdi’s office released a statement confirming the phone call and asked everyone “to spare no effort to prevent an escalation that will threaten all parties”.
“Unilateral decisions will trigger negative reactions that will make it more difficult to control the situation and will threaten Iraq’s security, sovereignty and independence,” he said.
Esper admitted it was unclear who exactly was attacking American interests.
“My suspicion would be that Iran is behind these attacks, much like they are behind a lot of malign behaviour throughout the region,” he said. “But it’s hard to pin down.”
Abdul Mahdi is a close ally of Iran and also enjoys cordial relations with the US.
He resigned in early December after two months of unprecedented demonstrations in the capital and Shia-majority south that have left at least 460 people dead.
Negotiations are under way to name his successor.
“If the Iraqi government or state weakens, this will exacerbate escalation and chaos,” Abdul Mahdi told Esper, according to the statement.
Iran has gained overwhelming influence in Iraq since the 2003 US invasion that brought down Saddam Hussein.
A US source recently told the AFP news agency that pro-Iran factions in Iraq were now considered a more significant threat to American soldiers than the armed group ISIL (ISIS).
The attacks have killed one Iraqi soldier and wounded others as well as damaged infrastructure in the vicinity of the US embassy in Baghdad’s ultra-secure Green Zone.
The US has recently reinforced its security at the embassy, according to an Iraqi security source, who said “a convoy of 15 American vehicles each transporting armoured trucks and weapons entered the Green Zone”.
Top US diplomat Mike Pompeo on Friday warned Iran’s leaders “any attacks by them or their proxies of any identity that harm Americans, our allies, or our interests will be answered with a decisive US response”.
US officials say they are considering sending 5,000 to 7,000 troops to the region to counter Iran. Esper on Friday again denied a report that a 14,000-strong deployment was under discussion.