The US Senate has advanced a measure to withdraw American support for a Saudi-led coalition fighting in Yemen.
In a blow to President Donald Trump, Senators voted 63-37 to take forward a motion on ending US support.
Secretary of State Mike Pompeo and Defence Secretary Jim Mattis had urged Senators not to back the motion, saying it would worsen the situation in Yemen.
The vote comes in the wake of the murder of Saudi journalist Jamal Khashoggi, a US resident.
Criticism of Saudi Arabia has grown since the prominent writer was killed while visiting the Saudi consulate in Istanbul in Turkey on 2 October.
The US Senators, who met in a closed session on relations with Saudi Arabia on Wednesday, also strongly criticised the non-appearance of the director of the CIA at their hearing.
Gina Haspel has heard a recording of Khashoggi’s murder provided by Turkey and has studied evidence in the case. One senator described her absence as a “cover-up”.
The Senate’s vote is seen as a rebuke to President Trump who has described Saudi Arabia as a vital ally and resisted calls for sanctions against the kingdom’s leadership.
Last week Mr Trump dismissed a reported CIA assessment that Saudi Crown Prince Mohammed bin Salman was to blame for Khashoggi’s death.
The vote in the Senate means further debate on US support for Saudi Arabia is expected next week.
Correspondents say that even if the Senate ultimately passes the bipartisan resolution it has little chance of being approved by the House of Representatives.
Situation in Yemen
The conflict began in 2014 when the Houthi Shia rebels seized control of the north of the country and went on to take the capital Sanaa, forcing the president to flee.
It escalated dramatically in March 2015, when Saudi Arabia and eight other mostly Sunni Muslim Arab states – backed by the US, UK and France – began air strikes against the Houthis, with the aim of restoring the government.
In recent weeks Houthi leaders have said they are ready to move towards a ceasefire if “the Saudi-led coalition wants peace”.
The coalition has recently ordered a halt in a fierce offensive on Hudaydah, a port on the Red Sea. They have also said that they support the UN-led talks.
The UN special envoy to Yemen, Martin Griffiths, has said he hopes peace talks convene before the end of the year.
The Houthis failed to show up at peace talks in September.