The Duke of Edinburgh, husband of Queen Elizabeth II, is hospitalized on Thursday, Buckingham Palace said.
Also known as Prince Philip, he has been admitted to the London Clinic "for an exploratory operation following abdominal investigations", according to a statement on the official website of the British monarchy.
"He is expected to stay in hospital for up to two weeks," said the statement.
The Duke of Edinburgh will be 92 on June 10. The longest-serving consort in Britain, he was not in good health in recent years.
He has been hospitalized for three times in the past two years due to blocked coronary artery and bladder infection, missing the Queen's Diamond Jubilee concert and closing ceremony of the Paralympics last year.