Boris Johnson today backed America's right to 'self-defence' as the fallout from Donald Trump's killing of Qassem Soleimani escalated.

The PM's official spokesman refused to criticise the dramatic drone strike despite threats from Tehran that UK forces could be 'collateral damage' in reprisals.

But Downing Street did caution that attacks on cultural sites - an idea Mr Trump has mooted - could break international law.

And the government has again appealed for Iraq not to expel British and US troops, pointing out that they are in the country to combat ISIS.

In a phone call with Iraqi counterpart Adil Abdul Mahdi today, Mr Johnson stressed his commitment to 'Iraq's stability and sovereignty' after the killing on its territory. He 'emphasised the importance of the continued fight against the shared threat' from the terrorist group.

Mr Johnson is back in Westminster after his Caribbean holiday, but finds himself walking a tightrope between Mr Trump and other allies who want to ease tensions.

He met Foreign Secretary Dominic Raab and Defence Secretary Ben Wallace this afternoon to take stock of the situation.

Speaking afterwards Mr Raab said: 'We have been very clear that cultural sites are protected under international law and we would expect that to be respected.'

Tehran moved today to quell speculation that British troops could be targeted by Iranian reprisals.

An unnamed commander told The Times: 'Our forces will retaliate and target US troops in Middle East without any concern about killing its allies, including UK troops, as this has turned into a fully fledged war with much collateral damage expected.'

But Iran's ambassador to the UK, Hamid Baeidinejad, dismissed the report as 'malicious false propaganda'.

He tweeted: 'As the Ambassador and high representative of my country in the UK, I strongly condemn the vicious lie and provocative news.'

A graphic showing British military strength in the Gulf and how it compares to that of other nations

The US strike on Friday and Iran's response to it has put British forces in the region on alert. This graphic shows where the UK has military assets in the area

Boris Johnson gathered key ministers for crisis talks today as the Iran crisis threatened to spiral out of control

Soleimani (left), the architect of Tehran's overseas clandestine and military operations as head of the Revolutionary Guards' Quds Force, was killed on Friday in a US drone strike (President Trump right) on his convoy at Baghdad airport

Foreign Secretary Dominic Raab (left) and Mr Johnson's key adviser Dominic Cummings (right) were at work in Whitehall today as the Iran crisis threatens to snowball

Defence Secretary Ben Wallace is also in Downing Street to take stock of the Iran standoff

Soleimani's body was returned to Iran on Sunday. People are seen carrying his casket upon arrival at Ahvaz International Airport in Tehran. The casket was greeted by chants of 'Death to America' as Iran issued new threats of retaliation

Iranians surround a vehicle carrying the coffin of Qassem Soleimani in the city of Mashhad, in northeastern Iran

British troops serving in the Middle East could 'possibly' be killed in retaliation attacks on US soldiers, according to retired army officer Sir Simon Vincent Mayall this morning.

Chaos as UK troops abandon their anti-IS missions in Iraq Britain's fight against ISIS is in chaos after the training mission in Iraq was ditched. Soldiers teaching local forces how to fight the militants were ordered to guard their bases instead amid fears that Iran could launch an attack in revenge for the killing of General Qassem Soleimani. Iraq's parliament also voted to boot out all US-led forces in response to the drone strike. If the vote is approved by the government, thousands of foreign troops including British soldiers, would be forced to leave, crippling the battle against the militants. Prime minister Adil Abdul Mahdi said it was 'time for American troops to leave for the sake of our national sovereignty'. The British government urged Iraq to allow UK soldiers to continue their training mission. More than 200 are stationed at Camp Taji, north of Baghdad, alongside American and German troops. Others are deployed in Erbil, northern Iraq, and there are a handful at two locations in Baghdad. Announcing the suspension of the training, a statement from the US-led mission against Islamic State cited rocket attacks in Iraq that were threatening the safety of coalition personnel. It added: 'As a result we are now fully committed to protecting the Iraqi bases that host coalition troops.' Former defence minister Tobias Ellwood said: 'This training suspension must not be permanent because it simply undermines the military efforts and huge resources put in to tackling Islamic State. 'This would lead to another reign of terror which will have repercussions far beyond the Middle East.' Advertisement

The lieutenant general told BBC Radio 4's Today programme that the allies were 'joined at the hip' in Iraq and that casualties could be shared if Iran strikes back following the US decision to kill Qassem Soleimani, a leading Iranian general.

The Ministry of Defence adviser said: 'I don't think the British are any more vulnerable than the Americans in this case - we are joined at the hip in this.

'But the Iranians are quite right. Because we're so closely joined in this, any attack on American assets will inevitably, possibly lead to to British casualties as well.'

Breaking his silence last night, Mr Johnson insisted Britain 'will not lament' the death of Qassem Soleimani.

He said the general, killed in a US drone strike in Baghdad on Friday, had played a role in the deaths of thousands of innocent people and was a 'threat to all our interests'.

But he also appealed to both Mr Trump and Iran for calm, urging both sides to encourage de-escalation.

Briefing reporters today, the spokesman said: 'States have a right to take action such as this in self-defence, and the US have been clear that Soleimani was plotting imminent attacks on American diplomats and military personnel.'

Former security minister Admiral Lord West has raised concerns that UK assets could be a 'softer target' than those of the US.

Meanwhile, Mr Trump has reacted with fury after Iraq said US and UK forces could be kicked out of the country. The president suggested the country could be hit with crippling sanctions if it follows through on the move.

The UK cautioned against the expulsion, saying it would give a major boost to ISIS just as the terrorist group seems to be on the back foot.

Washington says Soleimani was the architect of Iran's proxy wars across the Middle East and behind the deaths of hundreds of Americans in roadside bombings and other attacks.

Mr Trump issued a series of explosive tweets yesterday, threatening all-out war against the Iranian regime and boasted of the military arsenal at his disposal.

Referring to Iranian promises of retaliation published on social media, the US President tweeted: 'These media posts will serve as notification to the United States Congress that should Iran strike any U.S. person or target, the United States will quickly & fully strike back, & perhaps in a disproportionate manner. Such legal notice is not required, but is given nevertheless!'

Mr Johnson flew back from his holiday on the private island of Mustique yesterday, having ignored calls to return home early to deal with the crisis.

After landing in London, he held talks with Mr Trump, France's president Emmanuel Macron and German chancellor Angela Merkel.

Mr Johnson's spokesman said: 'The coalition is in Iraq to protect Iraqis and others from the threat from Daesh at the request of the Iraqi government.

'We urge the Iraqi government to ensure the coalition is able to continue our vital work countering this shared threat.

'The Foreign Secretary spoke to the Iraqi president and prime minister this weekend.

'The Prime Minister is speaking with his Iraqi counterpart today and our ambassador in Baghdad is in touch with political leaders in Iraq to emphasise these points and urge them to ensure we can keep fighting this threat together.'

The PM said in a statement last night: 'General Qassem Soleimani posed a threat to all our interests and was responsible for a pattern of disruptive, destabilising behaviour.

'Given the leading role he has played in actions that have led to the deaths of thousands of innocent civilians and western personnel, we will not lament his death.

'It is clear however that all calls for retaliation or reprisals will simply lead to more violence in the region and they are in no one's interest.'

He urged all sides to encourage de-escalation and said the UK had taken steps to boost the security of UK personnel and interests in the region.

Mr Johnson, Ms Merkel and Mr Macron released a joint statement overnight in which they again stopped short of criticising the US.

'We have condemned the recent attacks on coalition forces in Iraq and are gravely concerned by the negative role Iran has played in the region, including through the IRGC and the Al-Quds force under the command of General Soleimani,' they said.

'There is now an urgent need for de-escalation. We call on all parties to exercise utmost restraint and responsibility. The current cycle of violence in Iraq must be stopped.

'We specifically call on Iran to refrain from further violent action or proliferation, and urge Iran to reverse all measures inconsistent with the JCPOA.

'We recall our attachment to the sovereignty and security of Iraq. Another crisis risks jeopardizing years of efforts to stabilize Iraq.

'We also reaffirm our commitment to continue the fight against Daesh, which remains a high priority. The preservation of the Coalition is key in this regard. We therefore urge the Iraqi authorities to continue providing the Coalition all the necessary support.

Chancellor Sajid Javid was also at work in Downing Street today, but is not thought to be taking part in meetings on the Iran situation

'We stand ready to continue our engagement with all sides in order to contribute to defuse tensions and restore stability to the region.'

Ministers will meet today to discuss the situation and the National Security Council will gather later in the week. Parliament will be updated when it returns from recess tomorrow.

Retired lieutenant general Sir Simon Vincent Mayall told BBC Radio 4's Today programme that UK forces would be at risk because they were 'joined at the hip' with the US in Iraq.

Trump's drone strike could 'pay off', Jeremy Hunt says Donald Trump's dramatic strike on commander Qassem Soleimani could 'pay off', Jeremy Hunt said today. The former foreign secretary said the controversial killing was a 'bold move' - pointing out that Qassem Soleimani was behind 'regional instability'. 'I think it's easy to underestimate why it could have been a bold move that actually pays off because if there's one person who's responsible for regional instability - in Lebanon, in Syria, in Iraq, in Yemen - it was Soleimani,' he told Sky News. 'He was the hardline radical inside the Iran regime who had the ear of the Supreme Leader.' Advertisement

The Ministry of Defence adviser said: 'I don't think the British are any more vulnerable than the Americans in this case - we are joined at the hip in this.

'But the Iranians are quite right. Because we're so closely joined in this, any attack on American assets will inevitably, possibly lead to to British casualties as well.'

Lord West, a former head of the Royal Navy, warned that Britain could be a 'softer target' than the US for an Iranian retaliatory attack.

He told the Telegraph: 'Iran will assume that Britain would be party to any all out attack by the US.'

But former foreign secretary Jeremy Hunt said the dramatic step by the US could 'pay off'.

'I think it's easy to underestimate why it could have been a bold move that actually pays off because if there's one person who's responsible for regional instability - in Lebanon, in Syria, in Iraq, in Yemen - it was Soleimani,' he told Sky News.

'He was the hardline radical inside the Iran regime who had the ear of the Supreme Leader.'

Iran's nuclear announcement effectively ends its remaining commitments to a deal it agreed with Barack Obama. It said it would no longer observe restrictions on uranium enrichment or on research and development.

The statement noted that the steps could be reversed if Washington lifted its sanctions on Tehran.

The announcement came hours after hundreds of thousands of took to the streets to mourn Soleimani and chant 'death to America'.

The general's remains were carried through the cities of Ahvaz and Mashhad, ahead of a burial in his home town of Kerman tomorrow. One organiser for a funeral procession called on all Iranians to donate $1 each 'in order to gather an $80million bounty on President Trump's head'.

In a major blow for the fight against Islamic State, Iraq's parliament met for an emergency session yesterday and vowed to expel the 5,000 US troops in the country.

The vote still needs the approval of the Iraqi government, which has allowed a US-led presence to help combat the terror group. It had the backing of prime minister Adil Abdul-Mahdi, who said it was 'time for American troops to leave'.

The US-led coalition announced its troops had suspended training in order to focus on protecting bases from Iranian attacks.

Iran has issued a series of threats against the Americans, with the foreign minister warning that the days of US troops in the region were over.

Mohammad Javad Zarif tweeted: 'Whether kicking or screaming, end of US malign presence in West Asia has begun.'

Hezbollah leader Hassan Nasrallah warned in a televised address that US troops would pay the price for the killing of Soleimani by returning home in coffins.

Iranian lawmakers chant anti-American and anti-Israeli slogans to protest against the US killing of Iranian top general Qassem Soleimani at the start of an open session of parliament in Tehran, Iran, on Sunday

Tens of thousands of Iranians carrying the coffin of Qasem Soleimani while the crowds of mourners wept in the city of Mashad

Iranians gather around a vehicle carrying the coffins of slain major general Qassem Soleimani and others, as they pay homage in the northeastern city of Mashhad

Demonstrators attend a protest against the killing of Iranian Major-General Qassem Soleimani, head of the elite Quds Force, who died in an air strike at Baghdad airport, outside the US Consulate in Istanbul, Turkey

US Secretary of State Mike Pompeo has accused European allies of not being 'helpful enough' following the assassination.

Speaking on Sky News, Foreign Secretary Dominic Raab said: 'Let's be very clear: Soleimani was a regional menace, and we understand the position that the Americans found themselves in, and they have a right to exercise self-defence.

'They have explained the basis on which that was done, and we are sympathetic to the situation they found themselves in.'

Labour leader Jeremy Corbyn said Mr Raab's declaration of sympathy for the 'reckless and lawless killing was craven and dangerous'.