Saudi Arabia's King Salman bin Abdulaziz was admitted to hospital on Saturday in the Red Sea city of Jeddah to undergo medical tests, the state-run Saudi Press Agency reported on Sunday, citing a statement from the royal court.

He is undergoing the tests in the King Faisal Specialist Hospital, the statement said, giving no other details. “May God preserve the Custodian of the Two Holy Mosques and may he enjoy health and wellness,” the statement said.

Prime Minister Shehbaz Sharif took to Twitter to pray for the "early recovery and complete health" of the monarch. "The entire Pakistani nation joins me in praying for the early recovery and complete health of His Majesty King Salman bin Abdulaziz, the Custodian of Two Holy Mosques," he said.

King Salman, the custodian of Islam's holiest sites, became ruler of the world's top oil exporter in 2015 after spending more than two-and-a-half years as the crown prince and deputy premier.

He also served as governor of the Riyadh region for more than 50 years.

The king, 86, underwent gallbladder surgery in 2020 and had the battery of his heart pacemaker replaced in March.

The de facto ruler and next in line to the throne is the crown prince, Mohammed bin Salman, widely referred to as MBS, who has launched reforms to transform the kingdom’s economy and end its “addiction” to oil.