WASHINGTON, United States (AFP) — The United States (US) Senate passed a largely symbolic resolution Tuesday calling for an end to President Donald Trump’s war with Iran, delivering a fresh rebuke to the White House as it tries to negotiate a lasting settlement with Tehran.

The House-passed measure, adopted by the Senate in a 50-48 vote, directs Trump to remove US forces from hostilities with Iran unless Congress explicitly authorises military action.

Because the measure is a “concurrent resolution,” it does not go to Trump’s desk for signature and carries disputed legal force.

But its passage still puts both chambers of Congress on record against a conflict that began with US and Israeli strikes on Iran in late February, rattled global energy markets and opened a broader regional war involving Lebanon and Gulf states.

The vote came as the Trump administration pursued a 60-day diplomatic push to turn a preliminary memorandum of understanding with Iran into a final agreement covering Tehran’s nuclear programme, sanctions relief and the Strait of Hormuz.

Senate Democratic leader Chuck Schumer forced the vote to put Republicans on record after several Trump allies voiced alarm over both the war and the president’s deal to end it.

“Republicans can complain about Trump’s war, his secrecy, and his disastrous deal with Iran all they want behind closed doors, but the only way to ensure this war ends once and for all is for Republicans to act,” Schumer said in a floor speech ahead of the vote.

The resolution earlier cleared the Republican-controlled House after four Republicans joined every Democrat in backing it, a rare break with Trump on matters of war and national security.

Democrats say Trump violated the Constitution by launching military operations against Iran without congressional approval.

Under the 1973 War Powers Act, presidents must obtain authorisation from Congress within 60 days of introducing US forces into hostilities, though administrations of both parties have often contested how the law applies.

The White House has argued that resolutions seeking to curb Trump’s powers to wage war in Iran are unconstitutional and says the conflict had already ended under an April ceasefire ordered by Trump.

It has also warned that restricting the president’s authority could weaken Washington’s leverage as negotiators seek to lock in a final deal with Iran.

The vote also reflects growing unease in Congress over the cost of the war, which disrupted trade routes, drove up energy prices and placed new strain on US voters already worried about inflation ahead of November’s midterm elections.

The administration’s diplomacy with Tehran has moved quickly since Trump and Iranian President Masoud Pezeshkian signed the preliminary agreement, which was meant to halt the wider regional conflict and reopen the Strait of Hormuz.

But major disputes remain.

Iran said Tuesday that the UN nuclear watchdog would not be allowed to inspect nuclear sites bombed by the United States and Israel last year, rejecting Vice President JD Vance’s claim that Tehran had agreed to allow inspectors back in.

Trump later insisted on social media that Iran had accepted “the highest level” of nuclear inspections.