The Republican-led US Senate voted 50-48 to approve a measure urging President Donald Trump to end the war in Iran or seek congressional approval before continuing military action. Four Republicans joined Democrats in supporting the resolution.

However, the measure is largely symbolic and has no legal force, as it does not require Trump's signature. Trump dismissed it as "poorly timed and meaningless," arguing it could complicate efforts to secure peace with Iran.

The vote reflects growing concern in Congress over the unpopular conflict, which has driven up petrol prices and is approaching its fifth month. It is the first time since the 1973 War Powers Resolution that both chambers of Congress have approved a concurrent resolution directing a president to end military action.

Despite the vote, the White House says a ceasefire reached with Iran in April means there are no active hostilities requiring troop withdrawal. The US and Iran are currently working toward a broader agreement to end Iran's nuclear programme under a memorandum signed last week.