The US-led coalition is to scale back its operations in Baghdad and "reposition" troops after an order from Iraq's parliament.A letter, seen by Reuters, says the US will move the forces over the "coming days and weeks".However, US defence secretary Mark Esper said there had been "no decision whatsoever to leave Iraq".Iran's supreme leader cries at Soleimani prayersIt comes amid outrage at the US assassination of Iran's top military commander, Qassem Soleimani.Sky News correspondent Mark Stone said: "We understand around 1,100 forces in the green zone in Baghdad will be thinned out by a half or so."Some will be relocated within in Iraq, others in Kuwait."The plan we're told is that at some stage they will come back.

The rest of the coalition forces in Iraq will remain."Reuters says the letter is from William H Seely III, the American commander of Task Force Iraq, and that it has been independently verified.It reportedly reads: "Sir, in deference to the sovereignty of the Republic of Iraq, and as requested by the Iraqi Parliament and the Prime Minister, CJTF-OIR will be repositioning forces over the course of the coming days and weeks to prepare for onward movement."'Who will take revenge for my father's blood?'However, top US general Mark Milley, chairman of the Joint Chiefs of Staff, also sought to play down the letter.He said it was poorly worded and incorrectly implied withdrawal, when it was only meant to draw attention to increased troop movements.On Sunday, Iraq's parliament ordered all 5,000 US troops to leave the country following last week's assassination in Baghdad of General Soleimani.Soleimani's funeral in the Iranian capital Tehran drew huge crowds to the streets on Monday.Who was Qassem Soleimani?The country's supreme leader, Ayatollah Ali Khamenei, wept during prayers for the general, and his daughter warned that the US and Israel faced a "dark day".The drone strike on General Soleimani's vehicle killed the man regarded by many as the second most powerful person in Iran.Huge crowds accompany General Soleimani's coffinHe led the Quds unit of Iran's revolutionary guard and was responsible for expanding the country's influence in the Middle East - mainly through linked Shia militias.President Trump has hit back at Iran's vow of "severe revenge" by warning that the US military has identified 52 Iranian sites, including some of cultural significance.Britain has reduced staff at its embassies in Iran and Iraq to a minimum level as a precaution step, Sky News understands.The UK's ambassadors are believed to be staying put.Boris Johnson's spokesman has also tried to distance Britain from the US president's rhetoric.He said Britain believed the 2015 nuclear deal with Iran should be preserved, and there were "international conventions in place which prevent the destruction of cultural heritage".Iran has said it will no longer abide by restrictions on its uranium enrichment.Analysis by Mark Stone, Middle East correspondentThere was a remarkable turn of events late last night which exposes the US government's stark policy options for Iraq in the wake of the Soleimani assassination.

A letter by America's top general in Iraq to his Iraqi counterpart emerged on the pro-Iranian media outlet Al Ahed in Iraq.

On headed Pentagon paper it announced that the US military would "be repositioning forces prepare for onward movement We respect your sovereign decision to order our departure".

"Sir, in deference to the sovereignty of the Republic of Iraq, and as requested by the Iraqi Parliament and the Prime Minister, CJTF-OIR [the US-led coalition] will be repositioning forces over the course of the coming days and weeks to prepare for onward movement." the letter from Brig-Gen William Seely said.

It added that the US military would take measures to ensure that "movement out of Iraq is conducted in a safe and efficient manner and concluded: "We respect your sovereign decision to order our departure."A huge announcement.

The end of a 17 year presence in the country and a key demand of Iran.

Calls to the Pentagon we met with a statement that they "were looking into it."Forty-five minutes later the US Defence Secretary Mark Esper told reporters at the Pentagon that the letter was inaccurate.

"There's been no decision whatsoever to leave Iraq," he said.

Our own sources in Baghdad confirmed that the letter was genuine and that they too had seen it.

One source said their understanding of the US position was that a partial withdrawal or repositioning of some troops to Kuwait was taking place.

Then, back at the Pentagon, General Mark Milley, Chairman of the Joint Chiefs of Staff, was in front of reporters.

"It was a mistake," he said.

"That letter is a draft, it was a mistake, it was unsigned, it should not have been released poorly worded, implies withdrawal, that is not what's happening."Except, it doesn't imply withdrawal; it states it explicitly.A mistake then.

But a hint of a genuine withdrawal to come? Certainly it demonstrates policy options and confusion.