BEIRUT, Lebanon — United Nations experts broadened the inquiry into Saudi Arabia’s efforts to squelch criticism on Wednesday, accusing its crown prince of personally hacking the cellphone of Jeff Bezos, the billionaire owner of The Washington Post, to “influence, if not silence” the newspaper’s critical coverage of the kingdom.

The accusations, by two prominent United Nations rights experts, threatened to hamper efforts by Crown Prince Mohammed bin Salman to shake off the stigma of the 2018 murder and dismemberment of a Washington Post columnist by Saudi agents in Istanbul.

The experts did not directly investigate the hack, which The New York Times could not independently verify. But giving their imprimatur to an outside investigation bolstered criticism of the kingdom’s covert efforts to silence critical voices and widened the possibilities of who could be targeted.

“The hacking of Jeff Bezos is in a different league,” said Agnes Callamard, one of the United Nations experts. “He is not a Saudi citizen. He is a person of strategic interest, and his hacking appears to have been driven by his ownership of The Washington Post.”