Dubai (CNN Business) Saudi Arabia is attracting big names from around the world to advise on one of its most ambitious projects — building a futuristic mega city — even as questions mount about its role in the disappearance of prominent journalist Jamal Khashoggi.

Uber co-founder Travis Kalanick, SoftBank ( SFTBF ) CEO Masayoshi Son, venture capitalist and Facebook ( FB ) board member Marc Andreessen and Y Combinator President Sam Altman, are among the tech, science and business heavyweights who have agreed to serve on the project's advisory board, according to the official Saudi Press Agency.

Andreessen declined to comment about the project. Kalanick, Son and Altman did not respond to CNN requests for comment.

Others are distancing themselves from the $500 billion project, known as NEOM.

Dan Doctoroff, CEO of Sidewalk Labs, an urban innovation company owned by Google parent Alphabet ( GOOGL ), said his name should not have been on a list of advisers published by NEOM.

"Dan Doctoroff's inclusion on that list is incorrect," his spokesman said in a statement. "He is not a member of the NEOM advisory board."

Ernest Moniz, the former US Energy Secretary under President Barack Obama, said Wednesday he was suspending his participation on the advisory board "given current events."

"Going forward, my engagement with the advisory board will depend on learning all the facts about Jamal Khashoggi's disappearance over the coming days and weeks," he said in a statement.

Saudi Crown Prince Mohammed bin Salman announced the NEOM city a year ago, sitting alongside SoftBank's Son at an investment conference in Riyadh. Son described the plan to build an automated city of self-driving cars and passenger drones from scratch as a "fantastic opportunity."

It's one of the centerpieces of bin Salman's Vision 2030 , a blueprint for reshaping the kingdom's economy by increasing foreign investment, boosting tourism and selling a stake in its giant state oil company, Aramco.

Now, US intelligence is trying to determine whether the highest levels of the Saudi government were involved in the disappearance of Washington Post columnist and Saudi critic Khashoggi.

People hold posters of Saudi journalist Jamal Khashoggi during a protest outside the Saudi consulate on October 5, 2018 in Istanbul, Turkey.

Khashoggi was last seen more than a week ago entering the Saudi consulate in Istanbul. Top Turkish security officials have concluded that the "highest levels of the royal court" in Saudi Arabia ordered his assassination, according to a senior official cited by The New York Times.

Saudi Arabia has strenuously denied any involvement in Khashoggi's disappearance.

"At this stage, our priority is to support the investigation, as opposed to responding to evolving comments not directly related to those efforts," a senior Saudi official told CNN on Wednesday.

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The composition of the NEOM advisory board underscores the deep ties that already exist between the global tech industry and the kingdom.

Softbank and Saudi Arabia joined forces in 2016 to create the Softbank Vision Fund, raising $100 billion to spend on tech businesses. Its latest investments include $2.25 billion for GM's ( GM ) self driving unit.

"Each of the Advisory Board members has been carefully chosen," the Saudi Press Agency said in a statement on Tuesday listing the members. Additional members may be appointed, it added.

Boston Dynamics CEO Marc Raibert and former European Commission vice president Neelie Kroes have also agreed to serve on the advisory board, according to the SPA.