King Abdullah, who is about 87, left the kingdom on November 22 to undergo two operations in New York after a blood clot complicated a slipped disk. "I want to assure everybody that I'm well and I will return soon, very soon to the kingdom," Abdullah told the Kuwaiti daily, al-Seyassah on Monday.

Abdullah left a New York hospital on December 22 for an unspecified period of recuperation in the United States, Saudi state media said at the time.

King Abdullah, in power since 2005, has started a series of cautious reforms in the No. 1 OPEC oil exporter and U.S. ally, whose political stability is of regional and global concern.

Saudi Arabia controls more than a fifth of the world's crude oil reserves and is a major investor in U.S. government bonds.

Crown Prince Sultan, who also has health problems, returned from abroad before Abdullah's departure to run the country.

With both Abdullah and Sultan in their 80s, speculation persists that conservative Interior Minister Prince Nayef, 76, will take over, casting doubt over Abdullah's reform plans.