DONALD Trump has backed away from further military confrontation with Iran, claiming it “appears to be standing down” following missile attacks on two Iraqi bases used by Coalition forces.

No American casualties were reported, leading one Pentagon official to suggest the Iranian regime was "aiming to miss".

In a televised address from the White House, the US President announced he was imposing “additional punishing sanctions until Iran changes its behaviour”.

He emphasised America’s military might, saying: “Our missiles are big, powerful, accurate, lethal and fast. Under construction are many hypersonic missiles.

“The fact we have this great military and equipment, however, does not mean we have to use it. We do not want to use it.”

Mr Trump indicated there would be no military response to Iran’s retaliatory air strikes for the killing of the regime’s top general Qassem Soleimani.

Flanked by Mike Pence, the Vice President, Mike Pompeo, the Secretary of State, and military chiefs, he said: “Iran appears to be standing down. That is a very good thing for the world.”

Earlier, Ayatollah Khamenei, Iran’s supreme leader, described his country’s missile strikes as “a slap in the face” for America but warned Tehran still had a wider goal of expelling it from the Middle East.

Javad Zarif, the Iranian Foreign Minister, made clear the strikes had been “concluded”, saying they were “proportionate measures in self-defence” rather than an act of war.

At home, Downing St said Mr Johnson had had a phone conversation with Mr Trump before the presidential address. A No 10 spokesman explained the PM had stressed the need for "urgent de-escalation to avoid further conflict".

Earlier, during PMQs Mr Johnson criticised Jeremy Corbyn for not condemning the actions of Gen Soleimani, telling MPs: "That man had the blood of British troops on his hands."

But the Labour leader made clear if Britain stood by international law, then “surely killing somebody in a foreign territory is an illegal act and should be condemned as such”.

The PM replied how “most reasonable people would accept the US has a right to protect its bases and its personnel”.