Emperor Hirohito entered his fourth day in serious condition Thursday as the government turned over imperial duties to his son, Crown Prince Akihito, and postponed all major diplomatic activities.

Hirohito, 87, the world's longest reigning monarch who has seen Japan enter World War II and emerge from its ashes to become an economic superpower, suffered massive internal bleeding Monday night and underwent transfusions while being fed intravenously.An Imperial Palace spokesman said early Thursday there was no significant change in the emperor's condition after he was reported to have improved slightly Wednesday, adding the monarch had slept well Wednesday night.

The head of Hirohito's team of court physicians reported he is jaundiced and has an inflamed pancreas. Dr. Akira Takagi said there is no assurance the internal bleeding has stopped but an operation has been ruled out at present.

The cabinet formally requested Akihito, 54, to take over the emperor's ceremonial duties, but stressed the step is temporary. Akihito arrived at the palace Thursday to assume the duties.

Hirohito was considered a living god when he ascended to the Chrysanthemum throne in 1926 but was stripped of his status and all but symbolic duties after Japan's defeat in World War II.