US President Donald Trump during an interview said he does not need congressional approval to launch an attack against Iran.

"I do," Trump said on Monday when asked by The Hill newspaper if he believes he has the authority to attack Iran without getting approval from Congress. "We’ve been keeping Congress abreast of what we’re doing but I don’t have to do it legally."

US Democratic leaders have demanded that Trump get permission from Congress before launching any attacks against Iran or any other nation.

Trump last week said he called off a strike against Iran because the expected 150-person casualty rate was not proportional to the Iranians' downing of a US surveillance drone. Iran said the US drone violated Iranian airspace.