The resolution, adopted with four members of Trump's Republican Party joining Democrats, was largely symbolic, as the US president can veto the measure if it gains Senate approval.

Introduced by the ranking member of the opposition Democrats on the House Foreign Affairs Committee, the resolution passed by a vote of 215-208.

"This is a loud and unambiguous message to Donald Trump on behalf of the American people: it's time to end his deeply unpopular and illegal war of choice in Iran," the committee's Democrats posted on X.

It marked the first time the Republican-controlled House had approved a measure seeking to force Trump to wind down military operations against Tehran since the war began three months weeks ago.

A similar resolution passed a key procedural stage in the Senate at the end of May, and adoption by the upper house, which is also narrowly controlled by Republicans, could take place as early as this week.

The Trump administration insists that the war against Iran is already over, despite ongoing exchanges of fire between the two sides' forces and little sign of real progress in peace negotiations.