The Republican-controlled US Senate has approved a measure instructing President Donald Trump to halt the war in Iran or seek congressional approval before continuing military action.

A handful of Republicans joined Democrats in the 50-48 vote on Tuesday, marking a bipartisan show of disapproval of the war.

The same measure was passed by the US House of Representatives in June, where four Republicans joined every Democrat to approve it in a 215-208 vote.

But the resolution is largely symbolic because even after passing both chambers of Congress, it will not be sent to Trump for his consideration and does not carry the force of the law.

The vote marks the first time that both chambers of Congress have approved a concurrent resolution instructing a president to end a military action since the War Powers Resolution of 1973 was enacted.

Its passage is significant because it adds to the pressure the White House is facing to find an end to the Iran war, as petrol prices have spiked and public opposition to the war has increased.

But a White House official told the BBC that with the ceasefire agreed on 7 April, there are no hostilities from which to withdraw American forces.

The official also said the measure only passed because two Republican senators were absent: Mitch McConnell and Dave McCormick.

Four Republican senators voted with Democrats in support of the resolution: Rand Paul, Lisa Murkowski, Susan Collins and Bill Cassidy.

Democratic Senator John Fetterman was the only member of his party to vote against it.

It was the latest sign of division among Trump's fellow Republicans ahead of the midterm elections in November, which will determine whether the party can hold on to its slender majorities in both chambers of Congress.

Some Republicans have resisted the president recently, including by rejecting his plans to create a $1.8 bn (£1.3bn) "anti-weaponisation" fund and approving Ukraine aid.

Tuesday's vote was the 10th time that Senate Democrats have forced a war powers vote since the start of the war.

It came the same day as the Pentagon asked Congress for some $80bn, most of which is to pay for the war with Iran.

Federal law requires congressional approval to continue military actions for more than 60 days. The US-Israel strikes on Iran began on 28 February, although the Trump administration has argued that April's ceasefire reset the clock.

The White House can also extend the deadline for another 30 days, citing national security.

Currently, the US and Iran have agreed to continue a ceasefire and are working towards an end to hostilities under a memorandum of understanding signed by the presidents of both countries last week.

Under that memo, Washington and Tehran have 60 days to negotiate a broader agreement on ending Iran's nuclear programme.