JP Morgan & Chase's chief executive Jamie Dimon and Ford's chairman Bill Ford have cancelled plans to attend a Saudi investor conference.

They mark the latest such high-profile announcements after the disappearance of Saudi journalist Jamal Khashoggi. 

The cancellations could add pressure on other US firms like Goldman Sachs, Mastercard and Bank of America to reconsider their plans to attend the investor event. 

Neither JP Morgan nor Ford would elaborate on the reasons for the decision not to attend the Future Investment Initiative conference in Riyadh later this month.

They did not comment on whether concerns about the disappearance of Khashoggi were a factor. 

Khashoggi, a US resident and Washington Post columnist critical of Riyadh's policies, disappeared on October 2 after entering the Saudi consulate in Istanbul. 

Turkey believes he was murdered and his body removed. Saudi Arabia has denied that. 

The investment summit in Riyadh typically attracts executives from some of the world's largest companies and media organisations. 

But it has rapidly become a vehicle for those firms to express their concerns over Khashoggi's disappearance. 

Major news organisations such as CNN, the Financial Times, the New York Times, CNBC and Bloomberg have pulled out of the conference. 

The Fox Business Network, the lone Western news outlet still heading to the conference, told Reuters over the weekend that it was reviewing that decision. 

Uber Technologies chief executive Dara Khosrowshahi, Viacom CEO Bob Bakish and billionaire Steve Case, one of the founders of AOL, said they were no longer going.

Bill Winters, CEO of Asia, Africa and Middle East-focused bank Standard Chartered was still planning to go, the company said today. 

The absence of media and technology executives is likely to case a shadow over the three-day event, dubbed "Davos in the Desert." 

It has become the biggest show for investors to promote Saudi Crown Prince Mohammed bin Salman's reform vision. 

"Whilst it is disappointing that some speakers and partners have pulled out, we are looking forward to welcoming thousands of speakers, moderators and guests from all over the world to Riyadh," a Future Investment Initiative representative said last week.