The US House of Representatives has backed a resolution seeking to halt American military action in Iran, a symbolic move that deals a political blow to President Donald Trump as efforts to find a deal with Tehran stagnate.
Weeks of complicated talks marked by sharp rhetoric and flare-ups of violence have not managed to reach a deal to end the war and reopen the Strait of Hormuz, which is essential to oil supplies.
Washington and Tehran have sent divergent message in recent days, with Iran saying Wednesday "no tangible progress" was made, while Trump again voiced optimism by telling reporters at the White House "it could happen... over the weekend."
But in the latest episode of violence, Kuwaiti officials said renewed hostilities on Wednesday included an Iranian drone strike on a passenger terminal at Kuwait international airport that killed one person and wounded 63.
In the wake of the flare-ups, four lawmakers from Trump's Republican party joined Democrats on Wednesday to vote 215-208 in favour of the public rebuke.
The resolution was largely symbolic, as the US president can veto the measure if it gains Senate approval.
"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," Democrats posted on X.
At a congressional hearing, US Secretary of State Marco Rubio said Iran's highly enriched uranium stockpiles were at the centre of discussions with Tehran.
Washington insists Tehran must turn over its near-weapons-grade enriched uranium, agree to curb its nuclear activities and re-open the Strait of Hormuz, the key shipping channel for Gulf oil and gas, for any peace agreement to take hold.
Iranian Foreign Minister Abbas Araghchi said lines of communication with the United States were still open but warned that any Israeli attack on the Lebanese capital Beirut as part of its campaign against Iran-backed Hezbollah would trigger a "full-scale resumption" of the conflict.
"Communications with the Americans have not been cut off, and messages have been exchanged regarding the need to stop aggression against Beirut, but no tangible progress has been made in the negotiation process," the Tasnim news agency quoted Araghchi as telling Lebanon's Al Mayadeen TV.
"Any attack on Beirut will have grave consequences and will lead to a full-scale resumption of the war," he said. "Our armed forces are ready to strike Israel if it attacks Beirut."