Saudi Arabia’s Royal Court has announced that Crown Prince and Interior Minister Prince Nayef bin Abdulaziz al-Saud has died.

He died on 16 June. As crown prince, Prince Nayef was in line to succeed 89-year-old King Abdullah bin Abdulaziz al-Saud as ruler of Saudi Arabia. The Royal Court did not confirm the cause of death, although it had announced in May that he was travelling abroad for medical tests and a private holiday.

No official statement has yet been made on who will succeed Prince Nayef, who became crown prince in October last year, following the death of Prince Sultan bin Abdulaziz al-Saud.

Before becoming crown prince, Prince Nayef held the position of interior minister. Over the past 18 months he had become one of the most powerful figures in Saudi Arabia, leading the government’s response to the anti-government protests around the region that have resulted in the overthrow of rulers in Egypt, Libya and Tunisia, and seen widespread protests erupt in Bahrain and Syria.

Following the death of Prince Sultan, King Abdullah appointed his brother, Prince Salman bin Abdulaziz al-Saud, as defense minister in November 2011. However, the former governor of Riyadh was not named second deputy prime minister, a role that is traditionally the crown-prince-in-waiting. Prince Salman is still considered next in line to be appointed crown prince.

King Abdullah had established the Allegiance Council, a body made up of descendants of the founder of Saudi Arabia, King Abdulaziz al-Saud, in 2006 to appoint a new crown prince after the death of the king, however, King Abdullah has now outlived two of his crown princes. After the death of Prince Sultan in October 2011 the council met and selected Prince Nayef as his successor.

Prince Nayef had been considered a conservative, and reformists within the kingdom had worried about the direction of reform in the kingdom if Prince Nayef had taken the throne.