US Secretary of State Mike Pompeo decided May 8 to cancel his meeting with German Chancellor Angela Merkel and instead head to Iraq. The top USA diplomat made it clear that he was visiting Baghdad to discuss increasing tensions with Iran.
Ruled by Shiite clerics, Iran has a strong influence in Iraq, especially in the country's Shiite-majority south.
Only a week before Pompeo's surprise visit to Iraq, security forces reportedly thwarted an attack on Camp Taji north of Baghdad and seized a number of Katyusha rockets at the scene.
What do United States allies say?
Officials have spotlighted recent US decisions to deploy an aircraft carrier, strategic bombers and other military assets to reinforce troops across the Middle East. Amid rising tensions with Iran, Bolton said the decision was "in response to a number of troubling and escalatory indications and warnings".
US President Donald Trump on Wednesday predicted that Iran will "soon" want to negotiate and denied any discord in the White House over moves that critics say could lead to war in the Middle East.
On May 12, the embassy in Baghdad advised US citizens against travel to Iraq, citing "heightened tensions" in the country.
In spite of the military build-up near Iran, the New York Times has reported that any threat from Iran is small. Following the rise of the Islamic State, both Iran and the United States provided Iraqi security forces with training and equipment, with many from the PMF continuing to be backed by Iran.
The United States keeps about 5,000 soldiers in Iraq, who have been helping Iraqi security forces fight ISIS terrorists.
Yet the infrastructure that Iran has built in Iraq over the past years has provided it with exceptional leverage.
On Tuesday, Iran's supreme leader, Ayatollah Ali Khamenei, insisted the showdown between the Islamic republic and the United States was a mere test of resolve.
"Iran should be aware that it is principally responsible for the instability in the region", Gargash added and demanded that any future nuclear deal had to involve Arab states like his own.
On Instagram, an account linked to Maj. "Therefore we refuse any use of our territories because this poses as a violation of our sovereignty". Arbil is the Iraqi Kurdish regional capital, in northern Iraq.
Senior State Department officials, speaking on condition of anonymity, said that the threat came from Iraqi militias "commanded and controlled" by Tehran's Islamic Revolutionary Guard Corps. These groups played a vital role in Iran's proxy war during that period.
On Wednesday, the U.S. was more specific, saying there was an "imminent" threat to USA personnel in Iraq from Iraqi militias allegedly controlled by Tehran. The newspaper cited anonymous sources familiar with the matter.