Two key US Republican senators said yesterday after a briefing by the CIA's director they have "zero" doubt Saudi Arabia's crown prince directed the murder of the journalist Jamal Khashoggi.

The explosive new declarations by members of President Donald Trump's party run counter to the White House narrative downplaying possible links between Crown Prince Mohammed bin Salman and the October killing of journalist and palace critic Khashoggi at the kingdom's Istanbul consulate.

"I have zero question in my mind that the crown prince directed the murder and was kept appraised of the situation all the way through it," Senate Foreign Relations Committee chairman Bob Corker told reporters after CIA director Gina Haspel briefed a small group of senators.

"If MBS were in front of a jury he'd be convicted in less than 30 minutes."

CIA Director Gina Haspel. File Photo

Fellow Republican Senator Lindsey Graham, who has urged Trump to take a far tougher stance against Riyadh over the killing, also attended the hour-long briefing.

He minced no words afterwards, saying he believes Crown Prince Mohammed bin Salman is "a wrecking ball" who is "complicit in the murder of Khashoggi to the highest level possible."

"There's not a smoking gun but a smoking saw," Graham added.