Jamal Khashoggi latest: CIA says Saudi Crown Prince Mohammed bin Salman 'ordered killing of journalist'

The CIA has said Saudi Crown Prince Mohammed bin Salman ordered the killing of journalist Jamal Khashoggi in Istanbul, according to US media.

The agency’s finding, reported in the Washington Post, is the most definitive US assessment to date tying Saudi Arabia’s de facto ruler directly to the killing.

The Saudi government has insisted the prince wasn't involved, while he labelled the killing a "heinous crime".

Mr Khashoggi, a critic of the Saudi government and Washington Post columnist, was killed at the Saudi consulate in Istanbul on October 2. He went there to pick up documents needed for his planned marriage to a Turkish woman. Seventeen Saudis are said to have been involved in the killing.

The Post reported the CIA’s assessment was partly based on a phone call the Crown Prince's brother, Prince Khaled bin Salman – the Saudi ambassador to the United States – had with Mr Khashoggi.

Prince Khaled reportedly told Mr Khashoggi to go to the Saudi consulate in Istanbul to retrieve the documents, giving him assurances it would be safe to do so.

The newspaper reported he made the call at his brother's direction.

The Saudi Embassy in Washington rejected the CIA assessment.

A spokeswoman said: “The claims in this purported assessment is false. We have and continue to hear various theories without seeing the primary basis for these speculations."

It further complicates president Donald Trump’s efforts to preserve ties with Saudi Arabia, a key US ally.

Mr Trump has said Saudi Arabia must be held to account for any involvement in Khashoggi's death, but also stressed the importance of the alliance.

US officials say Saudi Arabia, a major oil supplier, plays an important part in countering what they see as Iran's “malign” role in the region.

On a visit to Papua New Guinea, vice-president Mike Pence told reporters he could not comment on classified information.

"The murder of Jamal Khashoggi was an atrocity,” he said. “It was also an affront to a free and independent press and the United States is determined to hold all of those accountable who are responsible for that murder.”

But he added Washington wanted to preserve its relationship with Saudi Arabia.

Additional reporting by Reuters.