Saudi Arabia's Crown Prince Nayef bin Abdulaziz, half-brother of King Abdullah and heir to the throne, died on Saturday (June 16th), AFP reported.

State media reported that the prince, a long-serving interior minister, died outside Saudi Arabia, having recently left the country for medical treatment. The nature of his illness has not been made public.

His funeral will be held Sunday after sunset prayers in Mecca, after his body is repatriated, it said.

The 79-year-old's death raises the issue of succession. King Abdullah himself is 88 years old and nobody is officially in line to replace Nayef, although his brother Prince Salman could be a candidate.

Nayef, who spearheaded Saudi Arabia's crackdown on al-Qaeda following a wave of attacks in the kingdom between 2003 and 2006, became heir to the throne in October 2011.