US President Donald Trump on Monday morning defended his decision to order the killing of Iranian commander Qassem Soleimani, contending Soleimani posed an impending threat to the United States but also saying that was not important given the military leader's history.

"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," Trump tweeted.

"The answer to both is a strong YES., but it doesn't really matter because of his horrible past!"

More:

Trump made the comments after retweeting several accounts criticising House Speaker Nancy Pelosi. One tweet the president shared included a fake photo-shopped image of Pelosi wearing a hijab and Chuck Schumer, the top Democrat in the Senate, with a turban. An Iranian flag was behind the two photo-shopped figures.

Since confirming that Soleimani had been killed by a US drone attack in Baghdad, administration officials have claimed they acted because of an imminent risk of attacks on American diplomats and service members in Iraq and throughout the region. The administration has not publicly released evidence supporting its claim, and comments over the weekend only raised new questions about what intelligence it used to order the strike.

Democrats and some Republicans in Congress have questioned the justification of the attacks and said they have not been given adequate, detailed briefings.

Conflicting information

Last week, Trump said in an interview that Iran had been poised to attack four American embassies before Soleimani was killed in a US drone attack on January 3. But on Sunday, the US defence secretary, Mark Esper, said he did not see specific evidence that Iran was planning an attack.

"What the president said was that there probably could be additional attacks against embassies. I shared that view," Esper said. "The president didn't cite a specific piece of evidence."

When pressed on whether intelligence officers offered concrete evidence on that point, Esper said: "I didn't see one with regards to four embassies."

Citing five current and former senior administration officials, NBC News reported on Monday, that Trump had authorised Soleimani's killing in June, with conditions, including that he would have final sign-off on any operation to kill the Iranian commander and the option would only be used if an American was killed by Iran.

Then-White House National Security Adviser John Bolton had urged Trump to retaliate for the drone downing by signing off on an operation to kill Soleimani, NBC reported, citing officials briefed on the discussions at the time. Secretary of State Mike Pompeo also supported the option, but Trump said he would only take the step if Iran killed an American, the US news outlet said.

War Powers

The House of Representatives and the Senate received separate briefings last week about the administration's decision to kill Soleimani.

Most Republicans defended Donald Trump, saying the US president made the "right call".

But two Republican senators - Mike Lee and Rand Paul - joined Democrats in slamming the briefings, calling them "insulting" and "demeaning".

The Democratic-controlled House on Thursday passed a nonbinding resolution aimed at limiting the president's ability to attack Iran in the future without congressional approval.

The House's War Powers resolution directs Trump to terminate military operations against Iran except for self-defence and clarifies that the president currently does not have congressional authority to engage in war with Iran. A similar version is expected to be debated in the Republican-controlled Senate, where it faces an uphill battle.

According to the US Constitution, the authority to direct military action is divided between Congress and the president. Congress has the power to declare war while the president, as commander-in-chief, has the power to use the military to defend the US.