US President Donald Trump has contradicted the CIA's reported assessment that Saudi Crown Prince Mohammed bin Salman ordered the killing of Washington Post columnist Jamal Khashoggi, insisting that the agency had "feelings" but did not firmly place the blame for the death.

Last week, senior intelligence officials from the US spy agency said that such an operation would have needed the approval of Prince Mohammed, also known as MBS, the kingdom's de facto leader.

Citing vehement denials by MBS and King Salman, Trump defended the Saudi monarchy on Thursday, saying they did not commit "this atrocity".

"I hate the crime, I hate the cover-up. I will tell you this: The crown prince hates it more than I do, and they have vehemently denied it."

Asked who should be held accountable for the murder, Trump again refused to place the blame - instead espousing a grim view of the world that he often shares with his advisers.

"Maybe the world should be held accountable because the world is a vicious place. The world is a very, very vicious place."

He also seemed to suggest that all US allies were guilty of the same behaviour, declaring that if others were held to the standard to which critics have held Saudi Arabia in recent days, "we wouldn't be able to have anyone for an ally".

Turkish Foreign Minister Mevlut Cavusoglu said Trump's comments indicated that he would turn a "blind-eye" to the incident.

Speaking to local broadcaster CNN Turk, Cavusoglu added that the US had not informed Turkey of an audio recording in which MBS can be heard calling for Khashoggi to be "silenced as soon as possible". (Aljazeera)