Emperor Hirohito, the world's oldest and longest reigning monarch, was reported in serious but stable condition Tuesday following massive blood transfusions as a worried government laid plans for the first succession in 62 years to Japan's 2,600-year-old Chrysanthemum throne.

Hirohito, 87, who ascended the throne in 1926 as a god but relinquished his divinity after World War II, was undergoing tranfusions that so far had replaced one-sixth of his blood, the Imperial Household Agency said.A team of three palace doctors worked around the clock to continue stablizing the emperor's ailment, which was believed to involve a swollen pancreas blocking the flow of bile from his gall bladder and causing jaundice.

Palace officials said only that the emperor's condition was stable, but doctors who have attended Hirohito in the past said the amount of blood given to the emperor in the past day indicated a serious state.

Officially, the court officials said Hirohito had received 1,000cc of blood in transfusions after spitting up blood and running a fever on Monday night. Doctors said the transfusions equalled one-sixth of the total blood supply of the frail emperor.

"His condition remains unchanged. Generally speaking his condition is stable," a palace official said late Tuesday.

There was wide speculation that the government would decide shortly whether to hand over the ceremonial duties of the emperor to the next in line, Crown Prince Akihito, 54. He and other members of the imperial family were at Hirohito's bedside most of the day.

The crown prince and his wife, Michiko, visited the palace three times and at one point took over the signing of official documents normally handled by the emperor.

Crown Prince Akihito automatically would become emperor upon his father's death and the government has reportedly started the process of succession and selection of a formal name for the era of a new emperor.

Palace officials said the gaunt emperor was sleeping at 4 p.m. after waking earlier in the day to greet members of his family in what was described as a "firm voice."

The emperor underwent intestinal bypass surgery on Sept. 22, 1987, to correct a similar problem.