Trump ordered attack on Iran, but then abruptly called it off

President Donald Trump said the US military was "cocked and loaded to retaliate" against Iran, but he changed his mind 10 minutes before planned strikes.

Attacks on three sites were planned in response to the shooting down of a US unmanned drone.

Planes were in the air and ships were in position, but no missiles had been fired when word came to stand down on Thursday night, the New York Times quoted an unnamed official as saying.

The newspaper further said the operation was under way "in its early stages" when Trump stood the US military down.

"I am in no hurry," Trump said on Friday. "Our Military is rebuilt, new, and ready to go, by far the best in the world.

Trump said he called off the strikes when he was told 150 people would die.

He tweeted: "10 minutes before the strike I stopped it, not proportionate to shooting down an unmanned drone".

It was not clear whether strikes would go ahead at a later date. The White House and Pentagon have not commented on the reports.

Tehran says the unmanned US aircraft entered Iranian airspace early on Thursday morning. The US maintains it was shot down in international airspace.

Tensions have been escalating between the two countries, with the US recently blaming Iran for attacks on oil tankers operating in the region. Iran has announced it will soon exceed international agreed limits on its nuclear programme.

Last year, the US unilaterally pulled out of a 2015 nuclear deal aimed at curbing Iran's nuclear activities.