PARIS (AP) — Senior government officials from the United States, France, Britain and the Netherlands joined a growing list of people cancelling out of an investment conference in Saudi Arabia amid questions over the kingdom's involvement in the disappearance of a dissident writer.

"I will not be participating in the Future Investment Initiative summit in Saudi Arabia," Treasury Secretary Steven Mnuchin wrote on Twitter.

Earlier, French Finance Minister Bruno Le Maire likewise said he would skip the conference known as "Davos in the Desert." Saudi Arabia had been hoping to use the event to help burnish its global image as a forward-looking country interested in new technologies and sustainable energy.

Le Maire said the disappearance of the dissident, Jamal Khashoggi, is "serious" and facts about it need to be explained by Saudi authorities. He added, however, that his decision doesn't call into question the strategic partnership between France and Saudi Arabia.

Dutch Finance Minister Wopke Hoekstra canceled after discussing the issue with Le Maire, the Dutch foreign minister said. Foreign Minister Stef Blok wrote that a Dutch trade mission planned for December to Saudi Arabia also likely will not go ahead.

Britain's trade minister, Liam Fox, later pulled out as well. Britain says it is "very concerned" about the disappearance of Khashoggi, who was last seen entering the Saudi consulate in Istanbul earlier this month. Turkish officials say he was killed and dismembered there.

Saudi officials have denied the allegations as "baseless," but haven't provided evidence of the writer leaving the diplomatic mission alive.

Several top business executives have also cancelled their plans to attend , as has the head of the International Monetary Fund, Christine Lagarde.