US Secretary of State Mike Pompeo's surprise visit to Baghdad this month came after US intelligence showed that Iran-backed Shiite militias placed rockets near bases holding US forces, according to two Iraqi security sources.
He told Iraq's top brass to keep track of the militias, which are expanding their power in Iraq and now forming part of their security device, said the sources. If not, the US would react with violence.
As tensions between Washington and Tehran increase, Iraq finds itself between neighboring Iran, whose regional influence has increased in recent years and the United States.
"The message from the Americans was clear. They wanted to guarantee that Iraq would stop those groups threatening US interests," said a senior Iraqi military source with knowledge of Pompeo's journey.
US Secretary of State Mike Pompeo's surprise visit to Baghdad this month came after US intelligence showed that Iran-backed Shiite military places rockets near bases that hold US forces, according to two Iraqi security sources. Pompeo is depicted with Russian President Vladimir Putin on Tuesday
"They said that if the US were attacked on Iraqi ground, it would take action to defend itself without coordinating with Baghdad."
The US Department declined to comment on details of Pompeo's discussions. He had said after the journey: "We do not want anyone to interfere in their country (Iraq), certainly not by attacking another nation in Iraq."
The second Iraqi security source said: "Communications listened to by the Americans showed some militia groups redistributed to raise suspicious positions that Americans considered provocations."
He said the Iraqis were told that any threat from the groups "would be dealt with directly of the Americans with violence. "
Iraqi premiere Minister Adel Abdul Mahdi on Tuesday told reporters that the Iraqi side had not observed" movements that pose a threat to any side. We explained it to the Americans – the government has a duty to protect everyone parties. "
The tensions between Washington and Tehran intensified early in the month when US President Donald Trump's administration increased the sanction pressure by ceasing except for some countries buying Iranian oil – part of the efforts to roll back the Islamic Republic's expansive regional complaint.
It also said last week that it sent additional military forces to the Middle East.
Iraq would struggle to force itself into the iranid militia.
The paramilitaries are formally part of Iraq's security forces but appear semi-autonomous, behind powerful Iranian ally politicians and expanding their economic power.  Spokesmen for two Iran-backed paramilitary groups said there were no plans to target US forces, saying that talk of threats was "psychological warfare" by Washington.
Iran sees Iraq as an important link to the world in front of US sanctions, and analysts say the placement of pro-Iran forces and rockets indicates that Tehran is prepared to at least threaten the United States with violence.
The Iraqi security source said US officials discussed with Iraqi officials, Iran-backed militia deployed along the Syrian border, where US troops have helped fight the Islamic state.
Last week, Pompeo said: "We have called on the Iraqi government … to get all these forces under the central control of Iraq."
The groups say they already follow orders from the Iraqi state and do not plan to target American interests.
"American claims are baseless. It reminds us of the great lie of weapons of mass destruction in Iraq," said Laith al-Athari, a spokesman for the Iran-backed Asaib Ahl al-Haq group, referring to the pretext for the US the leadership of Iraq 2003
The popular mobilization forces (PMF), the umbrella group of mostly Shiite military, are around 150,000 men.
There are currently an estimated 5,200 US troops in Iraq, which have reached the peak of 170,000 years after invasion.
Analysts say that the placement of missiles by militants supported by Iran is likely meant as a symbolic threat to the United States, rather than a real plan to use them.
Professor Toby Dodge of the London School of Economics said Iran has previously moved such weapons "to slowly shake up the heat of America in Iraq when it feels like America is striving to threaten Iran's interests".