Live updates: Follow the latest news on Iran war
The Republican-controlled US Senate on Thursday halted an attempt by Democrats to force President Donald Trump to end the war in Iran.
Democrats say the war is illegal because Mr Trump has not asked Congress for authorisation, or for politicians to declare war against Iran.
A procedural vote to advance the resolution, introduced by Senator Adam Schiff and other Democrats that sought to force Mr Trump to end hostilities, was defeated 50-47.
It was the sixth such attempt since the war began on February 28. Two Republicans crossed the aisle to vote with Democrats, while one Democrat went the other way.
The vote came on the final day of a 60-day deadline by which Mr Trump was supposed to seek authorisation for the war or ask for a 30-day extension to allow time to withdraw troops from the region.
Under the US Constitution, a president is allowed to start military action through his powers as commander-in-chief. But a 1973 law called the War Powers Resolution means Congress must either declare war or authorise a conflict within 60 days for it to continue.
It appears the Trump administration will ignore that deadline.
"In my view, this war was illegal from the start, because there was no attack on the United States [and] there was no imminent threat of attack," Mr Schiff told reporters before the vote.
Pentagon chief Pete Hegseth earlier claimed that the 60-day clock was on pause because of the ceasefire.
“We are in a ceasefire right now, which our understanding means the 60-day clock pauses or stops in a ceasefire,” he told the Senate armed services committee.
Democrats opposed the interpretation, saying the conflict is continuing because the US Navy is enforcing a naval blockade of Iranian ports.
"Here we are, over 60 days later, 14 American soldiers have been killed, hundreds of American troops wounded, thousands of civilians in the region killed, at least $25 billion of taxpayer money already burned," Democratic Senator Chris Van Hollen said on the Senate floor.
"We face even more regional instability in an already volatile part of the world. And we have an administration that cannot explain what it is they're trying to achieve."
But Mr Hegseth called the US effort in the war "stunningly effective" at blocking Iran’s nuclear ambitions and military capabilities, saying it had lifted Tehran's "umbrella of nuclear blackmail" over the region.
"If what you're seeing is success now, is winning, I would hate to see what losing looks like, because none of the shifting and contradictory objectives of the war so far have been achieved," Democratic Senator Richard Blumenthal told Mr Hegseth.
Foreign military sales
During his testimony before the committee, Mr Hegseth said the Pentagon was prioritising foreign military sales.
He said that previously, there was "no strategy behind ensuring we're sending the proper demand signal to industry, and delivering those systems on time and under budget to those countries, which you can imagine is frustrating to partners who are relying on those to be able to step up and burden-share."
In March, weeks after the war with Iran began, the State Department said it had made a determination approving possible foreign military sales to Gulf nations.
Mr Trump in February issued an executive order in which he ordered the prioritisation of "American interests by using foreign purchases and capital to build American production and capacity".
