US Treasury Secretary Steve Mnuchin
US Treasury Secretary Steve Mnuchin attends a Congressional Medal of Honor Society reception at the White House in Washington, DC, on September 12, 2018 NICHOLAS KAMM

US Treasury Secretary Mnuchin says he will not attend investment conference in Saudi Arabia known as the "Davos of the Dessert.".

Mnuchin joins a long line of VIPs and dignitaries from the world of business and politics who have returned their invitations to the Saudis in the wake of the disappearance of journalist Jamal Khashoggi, amid lurid reports of his murder at the hands of a hit squad, after he entered the Saudi consulate in Istanbul, Turkey, more thna two weeks ago.

Earlier, Secretary of State Mike Pompeo says he told Saudi Arabia's rulers that the U.S. takes "very seriously" the disappearance of Khashoggi and will await the outcome of investigations by the kingdom and Turkey before deciding how the U.S. will respond.

Pompeo addressed reporters Thursday after briefing President Donald Trump at the White House on his talks with leaders in Saudi Arabia and Turkey.

Pompeo says the Saudis assured him they will conduct a "complete, thorough" investigation into Khashoggi's disappearance.

Khashoggi is feared dead after entering the Saudi Consulate in Istanbul more than two weeks ago.

Turkish authorities say he was killed. The Saudis have denied involvement.

In his comments to reporters, Pompeo said he also stressed the "longstanding strategic relationship" between the U.S. and Saudi Arabia.

Who Is Missing Saudi Arabian Journalist Jamal Khashoggi?

On Tuesday, a pro-government Turkish newspaper has published a gruesome account of the alleged slaying of the Saudi writer who worked as a Washington Post columnist before his disappearance.

The report by Yeni Safak added to the ever-increasing pressure on Saudi Arabia to explain what happened to Khashoggi, who vanished October 2 while visiting the consulate to pick up paperwork he needed to get married. The Yeni Safak report cited what it described as an audio recording of Khashoggi's slaying, which it said showed the writer was tortured.

The newspaper said Saudi Consul General Mohammed al-Otaibi could be heard on the tape, telling those allegedly torturing Khashoggi: "Do this outside; you're going to get me in trouble."

The newspaper said one of the Saudis torturing Khashoggi replied: "Shut up if you want to live when you return to (Saudi) Arabia."

According to Middle East Eye, Khashoggi was still alive as Saudi forensics expert Salah Muhammad al-Tubaigy started to dismember the journalist on a table.

A Turkish source told MEE as he started to dismember the body, Tubaigy put on earphones and listened to music. He advised other members of the squad to do the same.

"When I do this job, I listen to music. You should do [that] too."

Earlier this week the New York Times reported another Turkish source who claimed that Tubaigy arrived in Istanbul equipped with a bone saw. Tubaigy, who is listed as the president of the Saudi Fellowship of Forensic Pathology and a member of the Saudi Association for Forensic Pathology, was part of a 15-man unit that arrived in Turkey aboard two private jets the night before Kashoggi's disappearance.