Saudi Crown Prince Sultan bin Abdulaziz al Saud has died, Saudi TV says.
The crown prince was King Abdullah's half-brother and first in line to the Saudi throne. He was also minister of defence and aviation.
He was in his eighties and was diagnosed with colon cancer in 2004. He is thought to have died at a New York hospital.
Prince Sultan had been on a visit to the US for medical tests, and he had an operation in New York in July.
The royal court confirmed the death in a statement carried by SPA, the state news agency:
"With deep sorrow and sadness the Custodian of the Two Holy Mosques King Abdullah bin Abdulaziz mourns the death of his brother and his Crown Prince Sultan... who died at dawn this morning Saturday outside the kingdom following an illness."