Saudi Arabia's Crown Prince Nayef bin Abdul Aziz Al Saud has died "outside the kingdom", state media say.
Prince Nayef, who was also deputy prime minister and interior minister, had left the country for a holiday and medical tests late last month.
On 3 June, the deputy interior minister said the prince, who was 77 or 78, was in good health and would return "soon".
Unconfirmed reports said Prince Nayef had been receiving medical treatment since May at a hospital in the Swiss city of Geneva.
The succession in Saudi Arabia still passes among the sons of former King Abdul Aziz ibn Saud, who established the modern kingdom during his reign from 1932 to 1953.