(CNN) The US moved closer to acknowledging the role of Saudi Arabia in journalist Jamal Khashoggi's apparent death as new details emerged linking his disappearance to people close to the kingdom's crown prince.

On Thursday President Donald Trump said for the first time that he believes Khashoggi is no longer alive, more than two weeks after the Washington Post columnist entered the Saudi consulate in Istanbul, never to be seen again.

"It certainly looks that way to me, it's very sad," the president said when asked if Khashoggi is dead.

Questioned about consequences for Saudi Arabia if it is found to be involved in his killing, Trump said: "Well it'll have to be severe, I mean it's bad, bad stuff. We'll see what happens. OK?"

They were Trump's strongest comments so far on the case.

A man holds a poster of Khashoggi during a protest at the entrance to Saudi Arabia's consulate in Istanbul on October 8.

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