US senators say they are more certain than ever after a private CIA briefing that the Saudi crown prince had a role in the murder of a journalist.
In a blistering attack, Senator Lindsey Graham said he had "high confidence" Mohammed bin Salman was complicit in the killing of Jamal Khashoggi.
The South Carolina Republican described the Saudi royal as "a wrecking ball", "crazy" and "dangerous".
The Saudis have charged 11 people but deny the crown prince was involved.
What did senators say?
Members of the Senate's Committee on Foreign Relations did not mince words after the briefing by CIA Director Gina Haspel on Tuesday.
"There is not a smoking gun - there is a smoking saw," Mr Graham said, referring to Khashoggi's alleged dismemberment in the Saudi consulate in Istanbul in October.
The senator said he could not support Saudi Arabia's involvement in the war in Yemen or arms sales to the Saudi government as long as the crown prince remained in power.
Senator Bob Menendez, a New Jersey Democrat, echoed those views.
He said the US must "send a clear and unequivocal message that such actions are not acceptable in the world's stage".
Another senator, Bob Corker, told reporters, using the crown prince's initials: "I have zero question on my mind that the crown prince MBS ordered the killing."
The Tennessee Republican added: "If he was in front of a jury, he would be convicted in 30 minutes. Guilty."
Mr Corker suggested that President Donald Trump had condoned the murder of a journalist by refusing to condemn the Saudi crown prince.
Fellow Republican Senator Richard Shelby of Alabama said: "Now the question is, how do you separate the Saudi crown prince and his group from the nation?"
The Senate is planning to vote on a proposal to end US military support to the Saudi-led coalition fighting in Yemen, after members of both parties advanced the resolution last week.
Senator Chris Murphy, who was not privy to Tuesday's briefing, criticised the Trump administration.
"Not everything needs to be secret," the Connecticut Democrat tweeted.
"If our government knows that Saudi leaders were involved in the murder of a US resident, why shouldn't the public know this?"
At some point Washington needs to have a good hard talk about the over-classification of information.— Chris Murphy (@ChrisMurphyCT) December 4, 2018
Not everything needs to be secret.
For instance, if our government knows that Saudi leaders were involved in the murder of a U.S. resident, why shouldn’t the public know this?
Senate aims to send tough message
Analysis by Barbara Plett Usher, BBC News, Washington
Senators are trying to pressure the White House into condemning the Saudi crown prince. Failing that they are exploring ways to send a message of their own that the US will not tolerate the blatant violation of international norms.
Options include blocking or suspending arms sales and imposing tougher sanctions. In a significant rebuke to the Trump administration, senators have already voted to advance a measure that would withdraw US military support for the Saudi-led war in Yemen.
But it won't be easy to get the numbers to actually pass the resolution, at least not in its current form. One difficulty is that while there is a lot of anger over the Khashoggi affair, there isn't agreement on the best way to respond. And any measures that senators might pass would almost certainly be blocked by the Republican-controlled House of Representatives.
So they would have to start over again when Democrats take control of the House next year, which they may well do. Given the legislative obstacles, and with full White House backing, Mohammed bin Salman doesn't have too much to worry about, at least for now. But the Saudis won't like being the ongoing object of Senate wrath, especially after paying millions and millions of public relations dollars to improve their image in Washington.
What has the CIA said?
The CIA has concluded Mohammed bin Salman "probably ordered" the killing of Khashoggi.
The spy agency has evidence he exchanged messages with Saud al-Qahtani, who allegedly oversaw the Saudi reporter's murder.
The CIA director - who has reportedly heard an audio recording of the murder - did not attend a recent congressional briefing by cabinet members, dismaying lawmakers.
The White House denied having a hand in Ms Haspel's conspicuous absence, and the CIA said no one had told Ms Haspel not to attend.
At last week's hearing, Secretary of State Mike Pompeo and Defence Secretary James Mattis told senators there was no direct evidence of the crown prince's involvement in Khashoggi's death.
President Trump has said the CIA findings on the crown prince were not conclusive.
On 20 November he said: "It could very well be that the crown prince had knowledge of this tragic event - maybe he did and maybe he didn't."
Who was Jamal Khashoggi?
As a prominent journalist, he covered major stories including the Soviet invasion of Afghanistan and the rise of Osama Bin Laden for various Saudi news organisations.
For decades the US resident was close to the Saudi royal family and also served as an adviser to the government.
But he fell out of favour and went into self-imposed exile in the US last year. From there, he wrote a monthly column in the Washington Post in which he criticised the policies of Mohammed bin Salman, including the war in Yemen.