US Senators have strongly criticised the non-appearance of the director of the CIA at a closed Senate hearing on relations with Saudi Arabia.
Secretary of State Mike Pompeo and Defence Secretary Jim Mattis gave evidence, but one senator described the absence of Gina Haspel as a “cover up”.
The Senate later voted to advance a move to end US support for the Saudi-led war in Yemen.
Criticism of Saudi Arabia has grown since the murder of a prominent writer.
Saudi journalist Jamal Khashoggi, a US resident, was killed while visiting the Saudi consulate in Istanbul in Turkey on 2 October.
President Donald Trump and his administration have 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 the death.
Several emerged from Wednesday’s briefing expressing anger that their request to hear directly from Ms Haspel – who has heard audio of the murder provided by Turkey – had been turned down.
Democratic Senator Bob Menendez said the Senate had been “stonewalled from hearing from the CIA director”.
“I have respects for the secretaries of state and defence but I don’t need them to characterise the information of the CIA and intelligence community, I need to hear it directly,” he added. “It’s time to send Saudi Arabia a message, both on its violation of human rights and the incredible humanitarian catastrophe it’s creating in Yemen.”
Republican Senator Bob Corker, who chairs the Senate Foreign Relations Committee, said it was apparent to everyone in the room that the crown prince had been responsible for Khashoggi’s death.
“We have a problem here. We understand that Saudi Arabia is an ally, of sorts, and a semi-important country. We also have a crown prince that’s out of control,” he said.
Another Republican Senator, Lindsey Graham, said he would be withholding his vote on any key issue until the CIA directly gives senators a briefing on the killing.
The BBC’s Barbara Plett Usher in Washington says opposition to the war in Yemen has gained momentum because of outrage at the administration’s response to the Khashoggi killing.
Later on Wednesday the Senate agreed by a vote of 63-37 to allow debate to proceed on a bipartisan resolution to end military backing for the Saudi led war.
The secretary of state restated the White House’s view that “there is no direct reporting connecting the Saudi crown prince to the order to murder Jamal Khashoggi”.
The Saudis have blamed rogue intelligence officers for the killing.
Mr Pompeo also defended the administration’s continued support for Saudi Arabia in Yemen, saying withdrawing it would undermine efforts to reach a ceasefire.
He said the US was “on a cusp” of gathering the warring parties for talks “to hopefully achieve a ceasefire”.
A vote, he added, would “encourage the Houthis” and their Iranian allies.
The conflict between Saudi-led military coalition and Houthi rebels has killed thousands of people and pushed millions more Yemenis to the brink of starvation.
The US provides intelligence support to the coalition and sells weapons used by the Saudis 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.