CNN  — 

Treasury Secretary Steven Mnuchin announced Thursday that he will not participate in a high-profile investor conference in Saudi Arabia amid growing controversy over dissident journalist Jamal Khashoggi’s disappearance and apparent killing.

Mnuchin announced his decision shortly after Secretary of State Mike Pompeo briefed President Donald Trump on his visit earlier this week to Riyadh to discuss the Khashoggi case. Pompeo urged patience with the Saudi investigation, telling reporters that he advised the President to give the Saudis “a few more days” – but Mnuchin followed up shortly afterward with a tweet saying he would not go to Riyadh, reversing the position he’s taken over the past week.

“Just met with @realDonaldTrump and @SecPompeo and we have decided, I will not be participating in the Future Investment Initiative summit in Saudi Arabia,” Mnuchin tweeted.

An administration official told CNN that no other government officials will attend next week’s summit in Mnuchin’s place.

The chief factor driving Mnuchin’s decision was the withdrawal on Thursday of several of his European counterparts, including ministers from France and the UK, according to a senior administration official. Both Mnuchin and Trump had been waiting to see what other countries would do before deciding themselves.

Another factor was pressure from business leaders who themselves had already made the decision to withdraw. In calls last week and over the weekend, top executives told Mnuchin they wanted to cancel and encouraged him to as well. But Mnuchin told them it was not his call, but Trump’s, according to the senior administration official.

Ultimately many top executives — including some close to Trump and his family — pulled out before Mnuchin. But Mnuchin’s plans remained in place, even as he relayed the concerns from the business leaders to Trump and Pompeo. Trump insisted no decision be made until other countries made their own announcements, the senior administration official added.

The Dow dropped 300 points, or 1.2%, on Thursday, with selling accelerating after Mnuchin’s tweet backing out of the conference.

Mnuchin’s attendance at the event had become a key benchmark of the administration’s response to the growing Saudi controversy as top bank executives and investors announced they were dropping out.

The treasury secretary, himself a former investment banker, had repeatedly said he planned to attend the Future Investment Initiative pending new information about the case, even as details reported in the Turkish and American press about the fate of the Washington Post columnist’s fate have grown increasingly gory.

Turkish investigators wearing hazmat suits searched the Saudi consul general’s residence in Istanbul on Wednesday, looking for clues to what happened to Khashoggi amid growing indications that the men allegedly responsible for the journalist’s death have close ties to the highest levels of the Saudi government.

Sources told CNN that a group of Saudi men whom Turkish officials believe are connected to Khashoggi’s apparent killing were led by a high-ranking intelligence officer, with one source saying he was close to the inner circle of the kingdom’s Crown Prince Mohammed bin Salman.

Emerging details triggered a number of top government officials to withdraw from participating in the event, including UK Trade Minister Liam Fox.

“The Secretary of State for International Trade has decided the time is not right for him to attend the Future Investment Initiative in Riyadh on 23 October,” said a UK government spokesman in a statement Thursday. “The UK remains very concerned about Jamal Khashoggi’s disappearance.”

The statement continued: “We encourage Turkish-Saudi collaboration and look forward to the Kingdom of Saudi Arabia conducting a thorough, credible, transparent, and prompt investigation, as announced. Those bearing responsibility for his disappearance must be held to account.”

French finance minister Bruno Le Maire also said Thursday he’s canceling his plans to attend next week’s conference, dubbed “Davos in the Desert.”

“The conditions have not yet been met for me to go to Riyadh,” Le Maire told French television’s Public Senat. “The facts are serious and we want to know the truth”, the minister said.

Dutch Finance Minister Wopke Hoekstra also withdrew on Thursday. A source familiar with the matter told CNN that “the minister is not going” to the Saudi conference. The finance minister was expected to submit a letter to the Dutch Parliament later Thursday formally confirming he is not attending.

Mnuchin told reporters during a Treasury press event Wednesday alongside Mexico’s finance minister that he would make a decision Thursday after Pompeo spoke with Trump. “We’re going to revisit the decision again tomorrow,” Mnuchin said. “So for now we are. We’re going to make a decision tomorrow based on Secretary Pompeo’s report.”

Christine Lagarde, the managing director of the International Monetary Fund, dropped out on Wednesday along with the heads of two major French banks: BNP Paribas and Societe Generale.

In recent days, Trump has repeatedly come to the defense of Saudi Arabia, saying the country’s crown prince “totally denied” knowledge about the suspected death of the Washington Post journalist and said answers into the matter would be coming “shortly.”

CNN’s Noah Gray, Matt Egan, Chris Liakos, Nada Bashir, Saskya Vandoorne and John Defterios contributed to this report.