BANGKOK -- Thailand's King Bhumibol Adulyadej, the world's longest-reigning Monarch, left hospital on Saturday following a hernia operation, the Bureau of the Royal Household said.

King Bhumibol, 75, has been treated for a range of ailments in recent years but is said to be in good health.

The king, on the throne since 1946, underwent 90 minutes of surgery on the right side of his groin on Tuesday and had been under observation since then.

"The panel of doctors, which have provided his treatment, reported that His Majesty's general condition is satisfactory to the extent that he can leave the hospital and return to his palace," the bureau said in a statement. King Bhumibol was last in hospital in June for a hernia operation on his left side. Surgeons removed a growth from the king's prostate gland in February 2002,

The quiet-spoken, bespectacled king, is widely revered by the Thai people, many of whom worship the royal family as semi-divine.

He has been a powerful force for national unity during a long series of military coups and constitutional experiments.

All factions have always claimed loyalty to him. Some 500 Buddhist monks, led by the supreme patriarch, gathered on Friday to pray for the health of the king at the temple of the Emerald Buddha at the grand palace in central Bangkok.