Japan's Imperial Household Agency says 101-year-old Princess Mikasa, whose given name is Yuriko, is in deteriorating condition with declining organ functions.

The princess is the widow of Prince Mikasa, a younger brother of the late Emperor Showa.

Princess Mikasa was hospitalized in March after suffering a stroke and aspiration pneumonia. She was treated at an intensive care unit at St. Luke's International Hospital in Tokyo. She has been recuperating in a private room since September.

The Imperial Household Agency says Princess Mikasa's condition has deteriorated, and tests carried out on Thursday showed declines in functions throughout her body, including the heart and kidneys.

Agency officials say the princess appears to be conscious. They say her condition has not worsened rapidly, and that the changes are due to her advanced age.

Princess Mikasa is the oldest living member of the Imperial Household since the Meiji period, which began in the late 19th century.

Agency officials say the princess' granddaughter, Princess Akiko, will cut short her visit to Britain and return to Japan on Saturday.