Saudi Arabia's King Abdullah will undergo surgery on Friday to stabilise vertebrae in his spinal column, the kingdom's royal court said in a statement carried by the state news agency.

The king, thought to be around 86 or 87, underwent surgery on his back in New York in November after a blood clot complicated a slipped spinal disc. The kingdom's health minister said afterward that his health was "very reassuring".
   
"King Abdullah...will undergo an operation on the afternoon of December 3 to stabilise some vertebrae in his spinal cord and complete the earlier surgery he underwent," the court statement said. 

It did not say where the new surgery would take place, but there has been no official word of the king leaving the United States.

A frail Crown Prince Sultan, who has health problems of his own, has returned home to govern the world's largest oil exporter while Abdullah is away for an unspecified period. - Reuters