BANGKOK (AFP) - Thailand's ailing King Bhumibol Adulyadej is recovering well after a recent operation to improve blood flow to his heart, the palace said, the latest in a series of major medical procedures for the 88-year-old.

In the latest update on his health released by the palace late on Sunday (June 12), doctors said the King was making progress with blood pressure and breathing back to normal.

An electrocardiogram also showed improved blood flow to the heart, the statement added.

Last Tuesday, doctors performed a series of angioplasty procedures without anaesthetic, using balloons and stents to widen multiple arteries in his heart.

King Bhumibol is the object of an intense personality cult and his frail health is a matter of significant public concern.

The King is confined to a wheelchair and rarely seen in public.

He has spent most of the past two years hospitalised in Bangkok for a series of ailments, including bacterial infections, breathing difficulties and hydrocephalus (water on the brain).

King Bhumibol is the world's longest-reigning monarch and most Thais have never known life under another king.

He is largely seen as a unifying force in a nation bitterly divided along political lines.

Anxiety over what will happen after his reign ends is considered an aggravating factor in the country's past decade of tumultuous politics, as competing elites jostle for power and influence before the transition.

Information on the monarchy is tightly controlled by the palace.

Throughout much of the last two years of Bhumibol's hospitalisation, updates have been rare.

But in recent weeks the palace has issued a string of health announcements.

Last month, doctors announced that he had been successfully treated for hydrocephalus as well as a lung and knee infection.

King Bhumibol has not been seen by the public since September when the palace released a video of him being taken in his wheelchair to visit a shop inside Bangkok's Siriraj hospital. Shoppers and attendants knelt and bowed as he passed by.

An official photograph of him attending a ceremony was released by the palace in December, while officials also released a statement in January saying he briefly left his hospital for an hour-long trip by car to visit a palace and other royal projects.

Discussion of his reign and the role of the monarchy is all but impossible because of the world's strictest lese majeste laws.

Use of the laws has skyrocketed in the last two years since the military took over in a coup with some people jailed for as much as 30 years.