Emperor Hirohito's vital signs worsened Tuesday and the 87-year-old monarch failed to respond for several hours to treatment for continued internal bleeding, a palace spokesman said.

Hirohito, who has been bedridden since Sept. 19 with suspected abdominal cancer, had a dangerously low blood pressure and a temperature of nearly 104 at 5:30 p.m., said Kenji Maeda, the chief palace spokesman.The emperor's temperature recovered to 99 and his blood pressure improved slightly by 8:30 p.m., Maeda said at an emergency news briefing.

Hirohito's blood pressure dropped considerably, he said. The abnormally low blood pressure level can cause brain damage if it is sustained over several hours.

Court physicians gave the emperor a blood transfusion in the afternoon but it failed to lift his blood pressure, the spokesman said.

The doctors then began trying other medicines in an attempt to return the emperor to stable condition, he said.

His blood pressure increased slightly by 8:30 p.m. and his chief physician, Dr. Akira Takagi, said the emperor was improving.

Takagi, who leads a team of five physicians, said he would spend the night at the palace to monitor the emperor's situation.

"The emperor is conscious, but he is tired from this afternoon and is now sleeping," said Maeda.

Prime Minister Noboru Takeshita said he was concerned by Hirohito's vital signs and would watch the situation closely.

Hirohito, who had been watching television in stable condition at noon, began bleeding internally in the afternoon and was given a transfusion of 1.2 pints of new blood, Maeda said.