President Donald Trump smiles while speaking at a campaign rally, Thursday, Jan. 9, 2020, in Toledo, Ohio. Picture: AP

Washington - US President Donald Trump on Monday took to Twitter to defend the targeted killing of top Iranian general Qassem Soleimani after critics questioned the "imminent" nature of the threat Trump said justified the move.

"The Fake News Media and their Democrat Partners are working hard to determine whether or not the future attack by terrorist Soleimani was 'imminent' or not, & was my team in agreement," the president wrote. "The answer to both is a strong YES., but it doesn't really matter because of his horrible past!"

Trump has justified the assassination by saying Soleimani was planning "imminent and sinister attacks" on US personnel, but has drawn ire for failing to produce evidence of such attacks.

The administration has also been criticized over conflicting statements on the rationale behind the killing. Defence Secretary Mark Esper on Sunday said he never saw evidence that Iran was planning an attack on four US embassies, as Trump had claimed two days earlier.

In a separate Monday tweet, Trump railed against "the Radical Left, Do Nothing Democrats" for scorning his policies.

"The Democrats and the Fake News are trying to make terrorist Soleimani into a wonderful guy, only because I did what should have been done for 20 years," he wrote.

The United States and Iran appeared on the brink of war after Trump ordered the killing of Soleimani earlier this month and Iran retaliated by firing ballistic missiles at US forces in Iraq.

Trump has since ordered additional sanctions on Iran, in what has been taken as a de-escalation of tensions.