BORIS Johnson has given Britain’s tacit support for Donald Trump’s decision to order the killing of Iran’s top general Qasem Soleimani, suggesting it was justified given the “leading role” the military commander played in the deaths of thousands of innocent civilians and Western personnel.

The fall-out to the US drone strike continued with Iraqi MPs calling for foreign troops to leave the country and Iran announced it would no longer abide by any of the limits imposed by the unravelling 2015 nuclear deal.

In a Downing St statement, the Prime Minister said 62-year-old Gen Soleimani, who headed the Islamic Revolutionary Guards’ Quds Force, had posed a “threat to all our interests and was responsible for a pattern of disruptive, destabilising behaviour in the region”.

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He declared: “We will not lament his death.”

Mr Johnson stressed: “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. We are in close contact with all sides to encourage de-escalation.”

The PM said he had spoken with Mr Trump, Emmanuel Macron, the French President, and Angela Merkel, the German Chancellor, and would be speaking with “other leaders and our Iraqi friends” in the coming days to support peace and stability.

He added: “We have taken steps to increase the security of our personnel and interests in the region. Following further international engagement and ministerial meetings here in the UK, Parliament will be updated on Tuesday.”

No 10 made clear Dominic Raab had already spoken to his US counterpart Mike Pompeo, whom he is due to meet on Thursday in what it described as part of a “long-planned” visit to the US. The Foreign Secretary had also spoken to Barham Salih, the Iraqi President, and Abdul Mahdi, its Prime Minister, as well as foreign ministers from France, Germany and Turkey, it said.

Mr Raab had earlier expressed “understanding” for Mr Trump's decision to launch the drone strike, accusing hardliners in Tehran of "nefarious behaviour" and saying the US had the "right of self-defence".

Today, Mr Johnson will discuss the Iran crisis with senior Cabinet ministers and the National Security Council will meet to discuss the matter later in the week.

The PM broke his silence on the US attack after returning from his Christmas holiday on the Caribbean island of Mustique, drawing criticism from Labour, which accused him of a dereliction of duty for not making clear his position on the pressing issue since the US drone strike at Baghdad Airport last Thursday.

Emily Thornberry, the Shadow Foreign Secretary, accused Mr Johnson of being preoccupied elsewhere, saying: “He's sunning himself, drinking vodka Martinis somewhere else and not paying attention to this.

"We've had three Cobra meetings where Mark Sedwill, the chief civil servant, has had to chair it because the Prime Minister hasn't been available."

Earlier, Sir Ed Davey for the Liberal Democrats was also critical, saying: "Johnson's silence on Trump's dangerous assassination in Iraq is deafening. The Prime Minister must speak out now and make clear Britain will not support the US in repeating the mistake of the Iraq war."

Mr Raab took to the airwaves to defend his colleague, insisting Mr Johnson was “in charge”.

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He told Sky News’s Sophy Ridge on Sunday: “In fact, I've been in constant contact with him over the Christmas break on a whole range of foreign policy issues.

"We were in touch on Friday with relation to the situation in Iraq and the whole Government is working very closely together. I spoke to the [US] Defence Secretary last night, I talked to the [US] National Security Adviser on Friday and we're very clear on the strategy and how we're implementing it and he'll be back in play tomorrow in the UK."

Ms Thornberry, a contender for the Labour leadership, suggested the Middle East was now facing the prospect of a major conflict and that, unlike the 2003 Iraqi war, Britain should not be dragged into it and “say no to the Americans”.

This was echoed by her colleague Sir Keir Starmer, who this weekend threw his hat into the ring to succeed Jeremy Corbyn as Labour leader, who declared: “We can’t blindly follow the Americans.”

As the political row broke at home, in Baghdad MPs voted to call on all foreign troops to leave Iraq in a non-legally binding move.

Mr Mahdi, the country's acting leader, called for “urgent procedures” to start a US exit, which he claimed was necessary to restore “our national sovereignty”.

Shortly after his statement, Washington announced it was suspending operations against the Islamic State terror group in Iraq together with a training mission to equip local forces. America has 5,200 troops in the country; any withdrawal would prompt fears that the battle against IS could be severely affected.

The Ministry of Defence was understood to be awaiting the decision of the Iraqi Government before acting over the 400 British soldiers based there as part of the US-led coalition.

A UK Government spokesman said: "The coalition is in Iraq to help protect Iraqis and others from the threat from Daesh [IS] at the request of the Iraqi Government.

"We urge it to ensure the coalition is able to continue our vital work countering this shared threat."

In Tehran, the Iranian government in a televised statement said it would no longer observe limitations on uranium enrichment, stockpiles of enriched uranium, or nuclear research and development. However, the statement pointed out this could be reversed if America abandoned its sanctions against Iran.

The political developments came after hundreds of thousands took to the streets in Iran to mourn the death of Gen Suleimani as his remains were carried through the cities of Ahvaz and Mashhad, ahead of his burial on Tuesday.

Earlier, Mohammad Javad Zarif, Iran’s Foreign Minister, struck back at the US President's Twitter threat to target 52 Iranian sites "very fast and very hard" if Tehran retaliated against US assets.

He accused Mr Trump of having "committed grave breaches" of international law with the killing of Gen Soleimani and of threatening to commit a "war crime" by targeting cultural sites.