Calls for Saudi Crown Mohammed bin Salman to be held accountable for the murder of Jamal are a "red line", Saudi Foreign Minister Adel al-Jubeir has said.

In a BBC television interview, Jubeir said on Wednesday any disparaging discussion about Mohammed or his father, the Saudi monarch, would not be tolerated.

"In Saudi Arabia, our leadership is a red line. The custodian of the two holy mosques (King Salman) and the crown are a red line," Jubeir said. "They represent every Saudi citizen and every Saudi citizen represents them. And we will not tolerate any discussion of anything that is disparaging towards our monarch or our crown prince."

Khashoggi, a US resident who wrote for The Washington Post and had been critical of Prince Mohammed, was lured to the Saudi consulate in on October 2, killed and reportedly dismembered.

After lengthy denials, Saudi authorities admitted responsibility and said 21 people had been taken into custody. However, a CIA analysis leaked to the US media went further, reportedly pointing the finger at the crown prince.

Jubeir insisted that Prince Mohammed had not been involved in the killing.

"We have made that very clear. We have investigations ongoing and we will punish the individuals who are responsible for this," he said.

He called on to come forward with all its evidence about the slaying and stop leaking out information.

The foreign minister said the murder was a "rogue operation" by intelligence officers.

Jubeir also said any possible US sanctions on would be short-sighted.

US on Wednesday ignored criticism that he gave a free pass on Khashoggi's murder, instead praising the Islamic kingdom for keeping low.