(CNN) -- Prince Salman bin Abdel Aziz has been tapped to be Saudi Arabia's defense minister, the royal court said Saturday.
He was governor of Riyadh, the country's capital, and is one of King Abdullah's brothers.
Prince Khaled bin Sultan was appointed as deputy minister to Prince Salman, the court said.
Saudi Arabia is one of the largest purchasers of arms from the United States and arms deals are conducted through the defense ministry.
Last month, Nayef bin Abdulaziz, Saudi Arabia's interior minister, was named the new crown prince of the key oil-producing nation after Crown Prince Sultan bin Abdulaziz Al-Saud, the king's half-brother, died in a New York hospital.
The shake-ups come at a tension-filled time in the Arab world.
The longtime leaders of Tunisia, Egypt and Libya have fallen in recent months during the so-called Arab Spring, while those in Yemen, Syria and elsewhere are holding on to power despite continuing popular unrest.
Violence remains a problem in neighboring Iraq, as well as Afghanistan. Iran, a longtime rival of the Saudi royal family's, is still at odds with much of the international community over its nuclear program, among other issues.