Donald Trump has said "rogue killers" may be behind the disappearance of Saudi journalist Jamal Khashoggi.

The US president also said Saudi leader King Salman denied "any knowledge of whatever may have happened" during a phone call.

He said King Salman had told him that Saudi Arabia is "working closely with Turkey to find answers", adding that he will be sending his secretary of state Mike Pompeo for further discussions with the ruler.

Speaking to reporters as he set off for Florida from the White House, President Trump said he did not "want to get" into the Saudi leader's mind, but added: "It sounded to me like maybe these could have been rogue killers.

"We're going to try getting to the bottom of it very soon, but his was a flat denial."


Just spoke to the King of Saudi Arabia who denies any knowledge of whatever may have happened “to our Saudi Arabian citizen.” He said that they are working closely with Turkey to find answer. I am immediately sending our Secretary of State to meet with King! — Donald J. Trump (@realDonaldTrump) October 15, 2018

Mr Khashoggi, a US resident and critic of the Saudi regime, went missing after visiting the Saudi Arabian consulate in Istabul on 2 October and Turkish officials believe he was murdered inside.

A joint Turkish and Saudi team will search the building later today amid a growing international backlash over the disappearance.

Saudi Arabia has said it will retaliate against any sanctions imposed against it over the case, after US President Donald Trump said the oil-rich kingdom deserves "severe punishment" if it is found responsible.

In a statement published by the state-run Saudi Press Agency, the kingdom warned if it "receives any action, it will respond with greater action, and that the kingdom's economy has an influential and vital role in the global economy".

"The kingdom affirms its total rejection of any threats and attempts to undermine it, whether by threatening to impose economic sanctions, using political pressures or repeating false accusations," the statement said.

Image: Jamal Khashoggi has been missing since 2 October

It gave no more details, but a column in English published shortly after by the general manager of the Saudi-owned Al-Arabiya news network said Saudi could use its oil production as a weapon.

International business leaders have steadily been pulling out of the country's upcoming investment forum, known as "Davos in the Desert".

They include the CEO of Uber - which Saudi Arabia has invested billions of dollars in - Richard Branson, JPMorgan Chase & Co chief executive Jamie Dimon, and Ford Motor Co executive chairman Bill Ford.

Britain, France and Germany have jointly called for a "credible investigation to establish the truth".

A statement encouraged a Saudi-Turkish effort to find out what happened, and, if relevant, to identify those responsible for the disappearance of Washington Post contributor Mr Khashoggi, and ensure they are held to account.

Turkish officials say he was killed and dismembered inside the building by a 15-member Saudi "assassination squad" and say they have evidence to support their claims.

They have not made any of the information they are basing their claims on public, although pro-government Turkish press reported that audio of the killing was recorded on Mr Khashoggi's Apple watch.

On Friday, it was reported that a delegation from Saudi Arabia had arrived in Turkey as part of a joint investigation.

On Sunday Saudi King Salman thanked Turkish President Recep Erdogan in a phone call for forming a joint team, saying no-one could undermine the relationship between the two countries.

UK 'extremely concerned' for Saudi reporter

UK Foreign Secretary Jeremy Hunt, French foreign minister Jean-Yves Le Drian and their German counterpart Heiko Maas said: "Defending freedom of expression and a free press and ensuring the protection of journalists are key priorities for Germany, the United Kingdom and France.

"There needs to be a credible investigation to establish the truth about what happened, and - if relevant - to identify those bearing responsibility for the disappearance of Jamal Khashoggi, and ensure that they are held to account.

"We encourage joint Saudi-Turkish efforts in that regard, and expect the Saudi government to provide a complete and detailed response."

The statement has also been delivered directly to the Saudi authorities.

Image: Mr Khashoggi had been critical of the Saudi de facto ruler

Mr Hunt later added that the UK would react if Saudi Arabia was behind the disappearance.

He said: "I don't want to get drawn into hypotheticals because we don't know the facts yet, but we have been very, very clear that if these stories are true, that would be totally appalling and we would have to think about the appropriate way to react in that situation."

In a letter seen by Sky News, several MPs wrote to Mr Hunt, demanding an investigation be opened into the disappearance.

Image: MPs sent a letter to Jeremy Hunt urging an investigation take place

Mark Menzies MP, the chair of the all-party parliamentary group on Saudi Arabia, is among 13 MPs who signed the letter.

Egypt has also called for a transparent investigation, but warned against the political exploitation of the case against Saudi Arabia.

Image: Saudi Arabia is run by Crown Prince Mohammed bin Salman

Mr Trump promised to get "to the bottom of it, and there will be severe punishment".

However, Mr Trump added the US would be "punishing itself" if it cancelled military sales to Riyadh over the disappearance of the Saudi journalist.

Turkey's Sabah newspaper, which claims Turkish officials now have the audio of the alleged killing, reports the recording was uploaded to a phone he had left with his fiancee and his iCloud, a storage facility.

It also reported that Saudi intelligence agents realised after he died that the watch was recording and tried to delete the file, first by incorrectly guessing Mr Khashoggi's PIN on the watch, then later using the journalist's finger.

However, unlike iPhones, Apple watches do not have a fingerprint ID unlock function.

Image: Mr Khashoggi entered the consulate to get papers he needed to marry his fiance

The newspaper's account also did not elaborate on how the Apple Watch synced the information to both the phone and iCloud account.

Saudi officials call all the allegations "baseless", but have offered no evidence Mr Khashoggi left the consulate.