Saudi King Abdullah bin Abdul Aziz is to undergo back surgery on Saturday, the royal court said, his third since becoming the ruler of the world's top oil exporter in 2005.
He was admitted Friday into a hospital in the capital Riyadh for medical tests before the surgery - to tighten a loose ligament, state news agency SPA reported citing the court statement.
In November 2010, Abdullah, 87, had a back operation in the United States after he was diagnosed with a blood clot in the spine and a herniated disc.
He underwent a second back surgery to retighten the binding connector around the third vertebra in the lower back in October last year, in Riyadh.
In June, he named his half-brother Salman, now 76, as heir apparent. - Sapa-dpa