RIYADH, Saudi Arabia — Saudi Arabia's King Salman has appointed his 31-year-old son Mohammed bin Salman as crown prince, removing the country's counterterrorism czar and a figure well-known to Washington from the royal line of succession.

In a series of royal decrees issued Wednesday and carried on the state-run Saudi Press Agency, the monarch stripped Prince Mohammed bin Nayef, who was first in line to the throne, from his title as crown prince and from his post as the country's powerful interior minister overseeing security.

The newly announced Crown Prince Mohammed bin Salman, who also serves as defense minister and oversees a vast economic portfolio, had previously been second in line to the throne, though royal watchers had long suspected his quick rise to power might accelerate his inheriting of the throne.

AP