In the aftermath of last week's U.S. military strike in Iraq which killed an Iranian paramilitary leader, the House voted mainly along party lines Thursday to assert its powers under the Constitution, to force President Donald Trump to end any military hostilities against Iran without the authorization and support of Congress.

"America is not a monarchy – the decision to go to war requires debate, deliberation, and collective judgment," said Rep. Betty Frankel (D-FL), as all but eight Democrats voted for the resolution.

Republicans denounced the non-binding measure as a partisan exercise meant to undercut President Trump.

"It is nothing but a blatant attempt to handcuff the President's ability to defend our citizens," said Rep. Jody Hice (R-GA).

Eight Democrats went against their leaders to vote against the plan, while three Republicans broke with President Trump.

Earlier in the day, President Trump defended his decision to use a drone strike to take out General Qassem Soleimani, the head of Iran's Quds force, blamed for attacks on U.S. troops in the Middle East.

"We caught a total monster, and we took him out," Mr. Trump said at an infrastructure event at the White House. "And that should have happened a long time ago. We did it because they were looking to blow up our embassy."

Amid complaints that the Trump Administration had not shown evidence of an 'imminent' threat from Soleimani, the President said the killing of an American contractor the week before was one clear reason to act.

"We had a shot at him, and I took it, and that shot was pinpoint accurate. And that was the end of a monster," Mr. Trump said.

At a campaign rally Thursday evening in Toledo, the President also made clear he felt the decision was the right one.

While the Senate is expected to vote on a War Powers Resolution dealing with Iran, it is a different form, making it unlikely that the House and Senate will agree on any plan - turning this House vote into more of a public rebuke.

"Our concerns were not addressed by the President's insufficient War Powers Authorization, which was classified in its entirety, leaving the Congress and the public in the dark about our national security," said House Speaker Nancy Pelosi.

"Congress is reasserting our long-established oversight responsibilities as we mandate that, if no further Congressional action is taken, the Administration's military hostilities with regard to Iran must end," the Speaker added.