Video report by ITV News Senior International Correspondent John Irvine
The US will not pull its troops out of Iraq the country's Defence Secretary has said, despite a letter from a US general there appearing to suggest it would.
The confusion came amid threats to American forces after the US killed top Iranian commander General Qassem Soleimani in Baghdad on Friday.
The document appeared to suggest the US was preparing to pull troops out of Iraq in response to a vote by the Iraqi parliament over the weekend.
The draft said troops would be "repositioning over the course of the coming days and weeks to prepare for onward movement", and warned of an increase in helicopter travel around the Green Zone (the centre of the international presence) in Baghdad.
It added: "We respect your sovereignty decision to order our departure."
The letter appeared to have been sent by Brigadier General William H Seely, head of the US military's task force in Iraq, to Abdul Amir, the deputy director of Combined Joint Operations.
But Defence Secretary Mark Esper told reporters the US is not pulling troops out of Iraq.
General Mark Milley, chairman of the Joint Chiefs of Staff, added that the "poorly written" letter was a draft which had been circulated internally by a US Marine commander and was an honest mistake that should never have got out.
ITV News Washington Correspondent Robert Moore explains the White House stance on the crisis
Gen Milley and Mr Esper said the US has been repositioning troops, largely due to increased security threats from Iran.
The letter was meant to co-ordinate with the Iraqi military on an increase in US helicopter and troop movements as they shift positions around the country.
"There's been no decision whatsoever to leave Iraq," Mr Esper said.
"There's no decision to leave, nor did we issue any plans to leave or prepare to leave."
Gen Milley acknowledged that some language in the letter "implies withdrawal", but that "is not what is happening".
"The long and the short of it is, it's an honest mistake," he said, adding that he had just got off the phone with the US commander in the Middle East, who explained the effort.
Mr Esper said the US remains committed to the campaign to defeat the so-called Islamic State group in Iraq and the region.
The letter comes amid soaring tension between the Middle East and the West following the assassination of Gen Soleimani in a US drone strike.
As well as anger directed at America, ITV News understands the number of staff at the UK's embassies in Iran and Iraq are being significantly reduced as a precaution, but they will remain open.
Tensions have increased further after US President Donald Trump threatened sanctions against Iraq if the 5,200 US troops were forced to go and warned America would target Iranian cultural sites if the Islamic Republic retaliated.
Gen Soleimani's killing sparked protests across his homeland, with his daughter vowing the United States faces a "dark day" as a consequence of its actions.
The UK, alongside France and Germany, has called for an urgent de-escalation.
Boris Johnson joined the head of NATO, and other world leaders, by urging restraint - and calling on both sides to get around the table to resolve the crisis following the targeted killing Gen Soleimani.
Foreign Secretary Dominic Raab called on all sides to diffuse the crisis as the UK attempts to walk a difficult diplomatic tightrope, trying to placate allies in the United States and the Middle East.
Mr Raab - who spoke to his Iranian counterpart Mohammed Javad Zarif on Monday - said the UK was stressing the importance of "de-escalating the tensions and finding a diplomatic way through this crisis" in talks with world leaders and foreign ministers.
US troops were instrumental in Iraq in the fight against so-called Islamic State.
Should foreign forces withdraw from Iraq, there are fears it could lead to the resurgence of the terror organisation.