06/07/2013 04:27 EDT | Updated 08/07/2013 05:12 EDT

Prince Philip Having Exploratory Surgery, Illness Unknown

EPSOM, ENGLAND - JUNE 01: Queen Elizabeth II and Prince Philip, Duke of Edinburgh watch the racing at The Investec Derby Festival at Epsom Racecourse on June 1, 2013 in Epsom, England. (Photo by Mark Cuthbert/UK Press via Getty Images)
LONDON - Britain's Prince Philip is facing exploratory abdominal surgery after being admitted to a London hospital.

Buckingham Palace says he is in good spirits and is expected to be in the London Clinic for up to two weeks after surgery on Friday.

The 91-year-old was admitted to the clinic, a private hospital and longtime favourite for the royals, after attending a garden party at Buckingham Palace. Philip appeared relaxed as he mingled with guests and told jokes at the party.

Officials have not released details about his condition but indicated he had had tests earlier in the week.

He had pulled out of one event this week but later attended a service at Westminster Abbey to mark the 60th anniversary of the coronation of his wife, Queen Elizabeth II.

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