The United States’ justification for attacking Iran over alleged “direct threats” does not meet the threshold required under international law to wage war, legal experts said.

U.S. and Israeli forces launched a massive air campaign against Iran on Feb. 28, with Washington claiming it aimed to curb nuclear and missile threats from Tehran. Yet the war has also decapitated the country's government, and President Donald Trump is now demanding "unconditional surrender."

The White House laid out Washington's justification for the war during a news conference this week.

"This decision to launch this operation was based on a cumulative effect of various direct threats that Iran posed to the United States of America, and the president's feeling, based on fact, that Iran does pose (an) imminent and direct threat," Press Secretary Karoline Leavitt said Wednesday.

She went on to cite Iranian sponsorship of "terrorism," its ballistic missile program and its alleged efforts to "create nuclear weapons and nuclear bombs."