Trump: 'rogue killers' might have slain missing Saudi journalist

US President Donald Trump said Monday that "rogue killers" could be to blame for the disappearance of a dissident Saudi journalist and said that the oil-rich state's monarch emphatically denies involvement.

"The denial was very, very strong," Trump told reporters at the White House after talking to King Salman by telephone. "It sounded to me like maybe these could have been rogue killers. Who knows?"

"All I can do is report what he told me. He told me in a very firm way that they had no knowledge of it. He said it very strongly," Trump said.

Trump said that Secretary of State Mike Pompeo was on his way to Saudi Arabia within the hour to discuss the controversy over journalist Jamal Khashoggi, a contributor to The Washington Post and critic of powerful Saudi Crown Prince Mohammed bin Salman.

Khashoggi vanished after visiting the Saudi consulate in Istanbul on October 2. Turkish sources say he was murdered there by a team of Saudi agents.

Trump has taken a cautious position, threatening "severe punishment" should proof emerge of Saudi guilt, but insisting that he will not risk billions of dollars in deals to sell US weapons to the kingdom, a strategic ally in the tinder box Middle East.

Following days of mounting tensions, Saudi officials were allowing Turkish investigators to enter the consulate on Monday.

A Turkish diplomatic source said it was expected that the search, to be conducted jointly with Saudi authorities, would "take place towards the evening."

Lurid claims have appeared in Turkish media, including that Khashoggi was tortured before being killed and cut up. However, the Turkish leadership has so far refrained from pointing the finger directly at Riyadh in public comments.

The controversy has also embarrassed Saudi Arabia's other traditional Western allies -- many of them arms suppliers to the kingdom -- and undermined efforts by the prince, Mohammed, to present himself as the modernizing future of the kingdom.

An investment conference seen as a platform for the crown prince, due to take place next week in Riyadh and dubbed "Davos in the Desert," has been hit by a string of prominent cancellations.

Business barons including British billionaire Richard Branson and Uber CEO Dara Khosrowshahi, as well as media powerhouses like Bloomberg and CNN, have pulled out of the Future Investment Initiative (FII).

In major new twin blows to the credibility of the event, JPMorgan Chase CEO Jamie Dimon and Ford chairman Bill Ford also cancelled plans to attend, CNBC reported.

In Washington, Trump's son-in-law and senior advisor, Jared Kushner, is coming under pressure after having spearheaded the administration's strategy to forge close ties with Mohammed.

But US Treasury Secretary Steven Mnuchin said on Saturday that he still plans to attend the Saudi conference.

"If more information comes out over the next week, I will obviously take that into account," he said.