The US Senate on Tuesday approved a resolution directing President Donald Trump to end the war with Iran or seek explicit congressional authorization for any further military action, with four Republicans joining Democrats in support of the measure.
The resolution passed the Senate by a vote of 50-48 after winning approval in the House of Representatives earlier this month.
The measure exempts military operations deemed necessary to defend the United States or its allies against imminent attacks.
The vote is largely symbolic and reflects growing opposition in Congress to the conflict with Iran. Democrats have accused Trump of launching the war without congressional approval, arguing that under the US Constitution only Congress has the authority to declare war.
Several Republicans who backed the resolution had previously criticized the framework agreement reached between Washington and Tehran to end the conflict, objecting to proposed sanctions relief and billions of dollars in reconstruction assistance for Iran.
Opponents of the measure argued it would have little practical effect because active hostilities have largely ceased since a ceasefire took hold.
Chuck Schumer, the top Senate Democrat, said Congress had rejected a "costly, unnecessary, and devastating war."
Representative Gregory Meeks, who introduced the resolution in the House, said the vote sent a clear message to the White House, arguing the conflict had failed to achieve key US objectives and had strengthened rather than weakened Iran.
Republicans, however, warned the measure could undermine ongoing negotiations with Tehran. Senator Jim Risch, chairman of the Senate Foreign Relations Committee, said it could encourage Iran to abandon the talks.
A White House official dismissed the resolution as having no significance, saying such measures are not submitted to the president for approval and do not carry the force of law.
The official also told dpa there were no ongoing hostilities from which US forces could be withdrawn following the ceasefire, adding that the measure passed only because several Republican senators were absent from the vote. Two Republican lawmakers did not participate.
