The eldest son of murdered Saudi journalist Jamal Khashoggi, Salah, and his family on Thursday left the Gulf kingdom after the government lifted a travel ban, Human Rights Watch said.
"Salah and his family are on a plane to (Washington) DC now," Sarah Leah Whitson, HRW's executive director for the Middle East and North Africa, told AFP.
There was no immediate comment from Saudi officials, but Whitson said that they were apparently allowed to leave after a travel ban on Salah was lifted.
Khashoggi has been missing since October 2, when he was last seen entering the Saudi consulate in Istanbul. The Turkish government has accused Saudi Arabia of murdering the dissident journalist and chopping his body into pieces.
Saudi Arabia admitted for the first time on Friday that Khashoggi was killed after entering the consulate in Istanbul, after previously denying Turkish claims that he was murdered.
On Thursday, Riyadh accepted what Turkey had said virtually from the start -- that Khashoggi was killed in a premeditated hit.
Khashoggi, who was also a US citizen and a contributor to The Washington Post, was a fierce critic of Saudi Crown Prince Mohammed Bin Salman and his policies.
US President Donald Trump earlier this week derided the killing as "one of the worst cover-ups" in history.
The United States has threatened sanctions if the Saudi leadership is linked to the murder, and on Tuesday revoked the visas of 21 Saudi nationals implicated in the crime.