Washington, United States (AFP) — US President Donald Trump yesterday demanded Saudi Arabia provide answers over the disappearance of respected journalist Jamal Khashoggi, whom Turkish officials suspect was murdered after he entered the Saudi consulate in Istanbul.

The Trump administration sharply upped the pressure, reversing an initially low-key response after Washington Post contributor Khashoggi vanished on October 2.

Trump said he had talked “more than once” and “at the highest levels” to partners in Saudi Arabia, which is one of Washington’s closest allies and a key market for the US weapons industry.

“We’re demanding everything,” Trump told reporters. “We cannot let this happen, to reporters, to anybody.”

“We are very disappointed to see what’s going on. We don’t like it and we’re going to get to the bottom of it,” he added.

Trump spokeswoman Sarah Sanders said National Security Advisor John Bolton, Secretary of State Mike Pompeo and Trump’s close aide and son-in-law Jared Kushner had all spoken to Crown Prince Mohammed bin Salman over the past two days.

US officials have not confirmed Turkish claims that Khashoggi, a US resident and one of the more outspoken critics of the regime of King Salman and his son Prince Mohammed, had been lured to the Istanbul consulate and murdered by a team of 15 government operatives sent by Riyadh to Istanbul.

The case has sparked outrage from human rights and journalism groups.

In the calls by Bolton, Kushner and Pompeo, Sanders said, “they asked for more details and for the Saudi government to be transparent in the investigation process”.

Trump also said he was looking into a meeting in the White House with Khashoggi’s fiancee Hatice Cengiz.

US peace activists Code Pink mounted a protest in front of the Saudi Embassy in Washington yesterday, brandishing signs saying “Where is Jamal Khashoggi?” and “Khashoggi: Another Victim of Saudi Violence”.

“We are very very disturbed” by Khashoggi’s disappearance, said Code Pink founder Meda Benjamin.

“We think that there is very little hope that Jamal is still alive.”

The Washington Post, where Khashoggi has been a regular contributor over the past year, also called for answers.

“Reports about Jamal’s fate have suggested he was a victim of state-sponsored, cold-blooded murder,” said Post publisher and chief executive Fred Ryan.

“Silence, denials and delays are not acceptable. We demand to know the truth,” he added.

Khashoggi, 59, is a long-time leading Saudi journalist and former government advisor who went into exile last year after 33-year-old Prince Mohammed rose to power underneath his father the king.

He has been critical of the monarchy’s continued arrest of critics on both the left and right, despite its professed reforms.

He has also repeatedly assailed Riyadh’s role leading the war against Yemen’s Houthi rebels, a campaign closely identified with Prince Mohammed that has resulted in thousands of civilian deaths and generated a major humanitarian disaster.

Khashoggi was last seen entering the Saudi consulate in Istanbul to obtain papers for his pending marriage to Cengiz, who is Turkish.

In his last interview three days before his disappearance, he said he did not think he would return to Saudi Arabia.

“When I hear of the arrest of a friend who did nothing that is (deserved being) arrested, it makes me feel I shouldn’t go,” he told the BBC.

Riyadh insisted that Khashoggi left the building and called the murder claims “baseless”.

Turkish investigators say they have CCTV footage showing him enter the consulate, but not leaving.

A source told The Washington Post that US intelligence “intercepted communications of Saudi officials discussing a plan to capture him”.

The Saudis hoped to “lure” Khashoggi to Saudi Arabia “and lay hands on him there”, the source told the Post.

But State Department deputy spokesman Robert Palladino told reporters they had no such tip.

“The US had no advance knowledge of Jamal Khashoggi’s disappearance” or of any kind of threat, he said yesterday.

The issue threatened the strong relationship the Trump administration has constructed with Mohammed Bin Salman.

The two sides have cooperated on challenging Iran, on supporting Israel and on the war against the Houthis.

But Prince Mohammed has drawn growing scrutiny over his campaign against critics.

Reporters Without Borders said in a statement that between 25 and 30 professional and non-professional journalists are currently detained in Saudi Arabia.