WASHINGTON (AFP) - US President Donald Trump is pessimistic about the fate of missing Saudi journalist Jamal Khashoggi, saying on Saturday (Oct 13) that it is "not looking too good" and he may have been killed.

Khashoggi, a Washington Post contributor and US permanent resident whose writings have been critical of powerful Saudi Crown Prince Mohammed bin Salman, has been missing since entering the country's consulate in Istanbul on Oct 2.

"I think we would've known by now. That was our first hope, our first hope was that he was not killed, but maybe that's not looking too good... from what we're hearing," Trump told journalists at the White House.

Turkish officials have said they believe Khashoggi was killed inside the consulate and lurid claims have been leaked to media that he was tortured and even dismembered, but Saudi Arabia insists he left the building safely.

The outcry surrounding his disappearance threatens to not just harm brittle Turkey-Saudi relations but also alarm the kingdom's supporters in the West and tarnish the reform drive spearheaded by the crown prince.