WASHINGTON (Reuters) - Top U.S. lawmakers turned their ire on Saudi Crown Prince Mohammed bin Salman on Sunday and said they believed he ordered the killing of Saudi journalist Jamal Khashoggi, although the Trump administration maintained a more cautious stance.

FILE PHOTO: U.S. Senator Bob Corker (R-TN) speaks with news media at the U.S. Capitol building in Washington, U.S., July 16, 2018. REUTERS/Leah Millis/File Photo

“Do I think he did it? Yes, I think he did it,” Republican Senator Bob Corker, the influential chairman of the Senate Foreign Relations Committee, said in an interview with CNN.

Corker, who received a classified briefing on the case on Friday, said he was waiting for investigations to be completed and hoped that Turkey would share any audio tapes of the killing of Khashoggi in the Saudi consulate in Istanbul on Oct. 2.

However, he made it clear that he believed the murder was directed by the prince, who has consolidated power in the world’s top oil exporter and courted U.S. President Donald Trump.

“Let’s let this play out, but my guess is that at the end of the day the United States and the rest of the world will believe fully that he did it,” Corker told CNN’s “State of the Union.”

The prince has denied involvement with the disappearance of Khashoggi, a critic of the government who wrote columns for the Washington Post and lived in the United States. Saudi Foreign Minister Adel al-Jubeir went on U.S. television to insist that the killing was a mistake, and sought to shield the prince from the widening crisis.

On Saturday, Trump joined European leaders in pushing Saudi Arabia for more answers after Riyadh changed its story and acknowledged that the journalist died at the consulate.

White House officials said on Sunday that Trump has not changed his belief that the crown prince is a strong leader who is passionate about his country. They said he and his advisers want to see the results of both the Turkish and Saudi probes.

Treasury Secretary Steve Mnuchin, who is traveling in the region, said the Saudi explanation was a “good first step but not enough.”

He said it was premature to discuss sanctions, in line with Trump administration efforts to censure a killing that has drawn international outrage while also protecting relations with the Saudis.

However, a number of Trump’s fellow Republicans joined their Democratic colleagues in Congress in expressing impatience with the shifting Saudi responses.

Corker said the Saudis have “lost all credibility” and fellow Republican Senator Ben Sasse said they “have a lot of explaining to do.”

Both Republicans and Democrats have turned their attention to the role of the prince, with whom Trump and his son-in-law and White House adviser Jared Kushner have cultivated a close relationship.

“I think it stretches credulity to believe the crown prince wasn’t involved in this,” Senator Rand Paul, a Republican close to Trump, said on “Fox News Sunday.”

“In Saudi Arabia, you do not do something of this magnitude without having clearance from the top,” Senator Thom Tillis, another Republican, said on NBC’s “Meet the Press.”

Three officials told Reuters that Trump’s relationship with his son-in-law has not been ruptured by Kushner’s ties to the crown prince. One source familiar with the situation said their relationship “could not be better.”

‘CROSSED THE LINE’

Senator Dick Durbin, the No.2 Democrat in the Senate, said he believed “the crown prince has his fingerprints all over this,” and called on the Trump administration to expel the Saudi ambassador and ask allies to do the same.

Corker said that if the prince had ordered the murder, “he’s now crossed the line, and there has to be a punishment and a price to pay for that.”

What that price will be is a thorny issue for Congress, as well as some European allies who also sell arms to the Saudis and have other business interests in the kingdom.

The United States could impose sanctions on the prince if he were found culpable in the killing, Corker said, but there should be a collective response with U.S. allies that are looking to Washington for leadership.

A number of lawmakers, including Paul, have called for an end to arms sales to Saudi Arabia.

Members of Congress have the power to block such sales. But Trump said last week he saw no reason to cut off weapons sales to Saudi Arabia in response to Khashoggi’s disappearance.

Corker said a nuanced response was needed.

“Sanctions are a blunt instrument. They’re good but they’re not that great,” Corker said. “And so we need to think of other ways to deal with this kind of behavior.”