Saudi Interior Minister, Prince Abdulaziz bin Saud bin Naif bin Abdulaziz, "stressed that what has been circulating in terms of supposed orders to kill Jamal are outright lies and baseless allegations against the Kingdom's Government, which is committed to its principles, rules and traditions and is in compliance with global laws and conventions".
"They demanded for what they called a "credible investigation" to establish the truth about what happened to Jamal Khashoggi and to identify those responsible for his disappearance".
Media and tech companies including Uber, Virgin and Viacom have withdrawn in protest at Khashoggi's alleged killing.
JP Morgan CEO James Dimon and Ford chairman Bill Ford said on Sunday they would also not attend.
U.S. President Donald Trump who has backed Saudi Arabia's King Salman has threatened his ally with "severe punishment" if Khashoggi, who has been critical of Crown Prince Mohammed bin Salman, was found to have been killed inside its Istanbul consulate.
Harris said there was no doubt Saudi Arabia had killed Khashoggi, describing that as "outrageous", but forecast the Government would want to wait a little longer to be "absolute" on what had happened.
He claimed there are many princes in jail right now in Saudi Arabia.
At Saudi Arabia's request, it's establishing a joint working group with Turkey to investigate Khashoggi's fate, Ibrahim Kalin, Erdogan's spokesman, told reporters on October 11.
But it has rapidly become a vehicle for those firms to express their concerns over Khashoggi's disappearance.
President Trump warned the United States would inflict "severe punishment" if Saudi Arabia was behind his disappearance. Media reports say the men were in the consulate when Khashoggi was there.
The main stock market index in Riyadh fell as much as 7% on Sunday and billions of dollars were wiped off the value of leading Saudi companies. The kingdom also warned of retaliation if there was any punitive action against it. "I don't think any of our government officials should be going and pretending it's business as usual until we know what's happening".
And in what could be an even bigger withdrawal from the event, Treasury Secretary Steven Mnuchin is now weighing whether to attend - after saying last week he did plan to go. The U.S. has called for an investigation.
The NTV channel said the delegation is composed of 11 people and had on Friday inspected the consulate in Istanbul.
"We heard about Khashoggi going missing the day before we were supposed to leave... and it just didn't feel like a smart move", the 48-year-old Scot told CNN on Saturday.