(CNN)Britain's Prince Philip was transferred to the King Edward VII private hospital in London on Friday morning, following a "successful" heart procedure on Thursday, Buckingham Palace said in a statement.
The move is the second in less than a week for the Duke of Edinburgh, the 99-year-old husband of Queen Elizabeth II.
He was transferred to St. Bartholomew's Hospital, also in London, on Monday for continued treatment of an infection and what the Palace said would be testing and observation for a pre-existing heart condition. On Thursday, the palace said he had undergone a heart procedure there.
"Following The Duke of Edinburgh's successful procedure at St Bartholomew's Hospital on Wednesday, His Royal Highness has been transferred to King Edward VII's Hospital this morning," Friday's statement read.
"The Duke is expected to remain in hospital for continuing treatment for a number of days."