London (CNN) -- Britain's Prince Philip, the husband of Queen Elizabeth II, was taken to Aberdeen Royal Infirmary in Scotland Wednesday afternoon as a precautionary measure, Buckingham Palace said.
It is not yet clear what has caused the concern for the 91-year-old Duke of Edinburgh, or what his current condition is.
He was taken to the hospital from the royal residence in Balmoral, Scotland, where the queen traditionally spends part of the summer, UK media reports say.
Prince Philip has suffered a couple of health scares in the past year.
He received hospital treatment for a bladder infection in June, after falling ill during events marking the queen's diamond jubilee.
In December, he spent four nights in a hospital over the Christmas holiday for treatment of a blocked coronary artery.
However, he appeared in good form earlier this week as he fulfilled several engagements on the Isle of Wight, off the south coast of England.
Philip's next scheduled public appearance is alongside the queen as she opens the London 2012 Paralympic Games on August 29.
He also appeared by her side at the opening ceremony for the Olympic Games at the end of July.
It has been a particularly busy year for the queen and Duke Of Edinburgh because of the many events held to celebrate her diamond jubilee.
The longest-serving consort in British history, Philip married then-Princess Elizabeth in November 1947 in Westminster Abbey.
Born the prince of Greece and Denmark on the Greek island of Corfu in 1921, Philip left Greece with his family when he was 18 months old after King Constantine was forced to abdicate the throne following a revolution. The family moved to Paris and then to England in 1928. Philip also went to school in Germany.
Philip renounced his Greek title when he became a naturalized British subject in 1947.
COWES, ENGLAND - JULY 25: Prince Philip, Duke of Edinburgh meets locals during Queen Eilzabeth II's Diamond Jubilee visit to the Isle of Wight on July 25, 2012 in Cowes, England.
