King Abdullah on Saturday named his half-brother Prince Salman, who is governor of Riyadh, as Saudi Arabia's defence minister to succeed the late Crown Prince Sultan, state television Al-Ekhbariya said.
Although Prince Salman served as governor for more than half a century, he has not previously held a ministerial post.
Prince Sattam bin Abdul Aziz was appointed Riyadh's governor in Prince Salman's place, the report said, citing a series of royal decrees, under which Prince Khaled bin Sultan, the late crown prince's son, was named deputy defence minister.
King Abdullah late last month named Interior Minister Prince Nayef bin Abdul Aziz as crown prince succeeding his brother Sultan, who died in a US hospital on October 22.
Salman, 76, who served as Riyadh's governor since 1955, and Nayef are full brothers. He was considered close to Sultan, whom he accompanied on his trips abroad for medical treatment.
Signup to our newsletter and follow us on Facebook and Twitter!
In 1960, Prince Salman resigned but he returned to the post three years later and has since been at the helm of the capital, winning credit for its development into a modern city.
With the appointment of Salman, King Abdullah is following the tradition of keeping top posts in the hands of the first generation of the sons of Abdul Aziz, founder of the kingdom.
Salman is the 25th son of Abdul Aziz and one of seven full-brothers known as the "Sudairi Seven", after their influential mother Hassa bint Ahmad al-Sudairi. The seven included the late king Fahd and Prince Sultan.
Married three times, Prince Salman has 10 sons, apart from two who have died, and a daughter.
The appointment of Prince Salman comes as Saudi Arabia, the world's largest oil exporter, is holding negotiations with the United States on the final details of a 60-billion-dollar arms deal.
The Pentagon unveiled plans on October 20 last year for the sale to Saudi Arabia of 84 F-15 fighter jets, 70 Apache attack helicopters, 72 tactical Black Hawk helicopters and 36 light helicopters, as well as upgrades for 70 F-15s.
The delivery of the weapons to the kingdom, thought to be the largest single US arms sale ever, would be spread across 15 to 20 years.