The US-based broadcaster CNN is claiming that Saudi Arabia is preparing a report “that will acknowledge that Saudi journalist Jamal Khashoggi's death was the result of an interrogation that went wrong”.

Quoting two sources privy to the matter, the CNN on Monday claimed that the interrogation involving Khashoggi was actually “intended to lead to his abduction from Turkey”.

Meanwhile, in a comment that seemed designed to give Saudi officials a route to climb down from outright denials, US President Donald Trump suggested on Monday that “rogue killers” could be responsible for the disappearance and presumed murder of journalist Jamal Khashoggi, who hasn't been seen since entering the Saudi consulate in Istanbul two weeks ago.

Trump's comment came after a 20-minute phone call with Saudi Arabia's King Salman in which Trump said the king adamantly denied any knowledge of what happened to Khashoggi.

The US president announced that he had dispatched Secretary of State Mike Pompeo to the kingdom and anywhere else necessary to get to the bottom of the apparent demise of Khashoggi, a Saudi who had been living and working in the United States.

“The king firmly denied any knowledge of it,” Trump told reporters, saying he didn't “want to get into [Salman's] mind,” but said: “It sounded to me like maybe these could have been 'rogue killers'. I mean, who knows? We're going to try getting to the bottom of it very soon, but his [Salman's] was a flat denial.”

The comments marked a break from the Trump administration's strenuous refusal to speculate over what happened to Khashoggi and came as the US president is under growing pressure to take action on the case of the Saudi writer, who was a contributor to The Washington Post and wrote columns critical of Saudi Crown Prince Mohammed bin Salman.

Trump last week vowed to uncover the truth about what happened to Khashoggi and promised “severe punishment” for those responsible.

Turkish officials say they believe Saudi agents killed and dismembered Khashoggi and say Turkey has audio and video recordings of it. The kingdom has called the allegations of foul play “baseless” but has offered no evidence the writer left the consulate.

In Istanbul, meanwhile, investigators entered the consulate for their own investigation. The members arrived by unmarked police cars but said nothing to journalists waiting outside as they entered the building.

Turkish officials have earlier said they fear a Saudi hit team that flew into and out of Turkey on October 2 killed and dismembered Khashoggi.

International concern continues to grow over the writer’s October 2 disappearance. American lawmakers have threatened tough punitive action against the Saudis, and Germany, France and Britain have jointly called for a “credible investigation” into Khashoggi’s disappearance.