Media playback is unsupported on your device Media caption Senators slam Saudi crown prince as 'crazy' and a 'wrecking ball'

The US Senate has voted to withdraw US military aid for Saudi Arabia's war on Yemen and to blame the kingdom's crown prince for the murder of a journalist.

The historic vote is the first time any chamber of US Congress has agreed to pull US forces from a military conflict under the 1973 War Powers Act.

Some of President Donald Trump's fellow Republicans defied him to pass the measure with Democrats by 56-41.

But the resolution is seen as largely symbolic and unlikely to become law.

What did the Senate actually do?

The non-binding "war powers resolution" calls upon President Trump to remove all American forces engaging in hostilities in Yemen, except for those combating Islamist extremists.

The Senate then unanimously passed a resolution blaming Saudi Crown Prince Mohammed bin Salman for Washington Post reporter Jamal Khashoggi's murder in October, and insisting that the kingdom hold accountable those responsible.

The US chose to cease refuelling Saudi war planes last month, and Thursday's resolution - if it were ultimately passed into law - would prohibit that practice from resuming.

Image copyright Reuters Image caption President Trump has consistently defended US business and military ties with Saudi Arabia

What did senators say?

Independent Vermont Senator Bernie Sanders, who co-sponsored the measure with Republican Mike Lee of Utah, hailed the vote.

"Today we tell the despotic government of Saudi Arabia that we will not be part of their military adventures," he said.

He described the outcome as a signal to "the world that the United States of America will not continue to be part of the worst humanitarian disaster on the face of the earth".

Republican Senator Bob Corker told MSNBC: "If he was before a jury, the crown prince, he would be convicted in my opinion in 30 minutes."

Status quo no longer acceptable

Analysis by Barbara Plett, BBC State Department Correspondent

The two resolutions send a strong message that for a majority of senators, the status quo with Saudi Arabia is no longer acceptable.

They value the strategic relationship but are deeply uneasy about the leadership of Crown Prince Mohammed bin Salman. They have viewed his foreign interventions with growing concern, especially the human cost of the war in Yemen.

But it was the grisly murder of Jamal Khashoggi that tipped the scales: it dramatically increased support for the resolution to withdraw US military support for the Saudi-led campaign in Yemen, something that failed to pass earlier in the year. Many senators saw the Khashoggi killing as the blatantly egregious act of an ally that felt immune from rebuke.

And they were dismayed when the administration stood staunchly by the prince without censure, even though the CIA concluded he probably ordered the killing. Senators want to see the administration shape the alliance as the senior partner, and enforce red lines.

Senior Republican Senator Bob Corker noted recently that much of the bipartisan activism in the Senate had been fuelled by a perception that there is no balance between values and interests in the administration's policies.

Can this legislation become law?

President Trump has vowed to veto the measure, and it is unlikely right now to pass the House of Representatives, which on Wednesday blocked a vote on the matter.

But Senator Sanders said he expects the resolution to succeed once Democrats formally take over control of the House in January following their mid-term elections victory.

The Trump administration had argued the bill would undercut US support for the Saudi-led coalition against Iranian-backed Houthi rebels in Yemen.

White House officials have emphasised US economic ties to the kingdom. Mr Trump's adviser and son-in-law, Jared Kushner, has continued to cultivate ties with the prince, according to the US media.

What's the latest in Yemen?

A ceasefire agreed by the warring parties on Thursday has come into effect in the country's main port, Hudaydah.

Image copyright Getty Images

After the deal was reached in Sweden, negotiators for both parties shook hands to applause, though they later expressed scepticism.

UN Secretary General Antonio Guterres said he hoped this would be the starting point to bring nearly four years of civil strife to a close.

Since hostilities began in 2014, thousands of civilians have been killed, and around 14 million people have been pushed to the brink of starvation, according to the UN.

Saudi Arabia buys the bulk of its weapons from the US, Britain and France.