Two members of the Saudi royal family are believed to have been arrested for allegedly plotting to oust King Salman and Crown Prince Mohammed bin Salman.
According to reports, guards detained one of the king's brothers, Prince Ahmed bin Abdulaziz al Saud, and one of his nephews, Prince Mohammed bin Nayef.
Both men were arrested at their homes and charged with treason, according to the Wall Street Journal.
There has been no immediate comment from Saudi authorities on the reports.
Mohammed bin Nayef, once a powerful figure as head of Saudi counter-terrorism efforts, had been crown prince until 2017, when King Salman took away the title and put his son first in line for the throne.
The crown prince, who is in charge of day-to-day governance in the kingdom, had been praised in the West for implementing social reforms , but he also has drawn criticism for a tough crackdown on critics of his policies.
Mohammed bin Salman came under criticism after the 2018 killing of dissident and Washington Post columnist Jamal Khashoggi inside the Saudi consulate in Istanbul.
Critics accused him of being linked to the killing but he denied any involvement.