US senator Lindsey Graham accuses 'wrecking ball' Saudi crown prince of ordering Khashoggi's murder

US Senator Lindsey Graham says he believes Saudi Crown Prince Mohammed bin Salman had a US-based journalist "murdered" in the Saudi consulate in Turkey and has "tainted" his country as a result.

The influential Republican and ally of President Donald Trump said the crown prince "has got to go", adding he will not return to Saudi Arabia while the prince is in power.

Graham says he has been the "biggest defender" of the kingdom, but that he now plans to "sanction the hell out of Saudi Arabia".

Speaking on Tuesday on Fox & Friends, the senator cited published reports that Prince Mohammed had approved an interrogation or rendition of Khashoggi back to Saudi Arabia, and that an intelligence official who was a friend of the crown prince had killed the journalist.

"I've been their biggest defender on the floor of the United States senate. This guy is a wrecking ball, he had this guy murdered in a consulate in Turkey and expects me to ignore it. I feel used and abused.

"I've been on the floor every time defending Saudi Aabia because it's a good ally but there's a difference between a country and an individual. The MbS figure is to me toxic. He can never be a world leader on the world stage."

Khashoggi vanished after entering the Saudi consulate in Istanbul on 2 October to carry out marriage paperwork.

Turkey has said it fears Khashoggi was killed by a Saudi hit team. Saudi Arabia has denied that, but published reports  have said the kingdom may be preparing to acknowledge killing the journalist during an interrogation gone wrong.