Updated

Prince Philip was transferred to another London hospital to continue treatment for an infection, Buckingham Palace said Monday.

Per the palace, Philip, 99, was transferred from King Edward VII’s Hospital to St Bartholomew’s Hospital. The Bart's Heart Centre is Europe's biggest specialized cardiovascular center, the National Health Service said.

In addition to treatment for an unspecified infection, the husband of Queen Elizabeth II, will also undergo testing and observation for a pre-existing heart condition.

Philip was admitted to the private King Edward VII’s Hospital last month after feeling ill. Royal officials called his hospital admission a precautionary measure.

PRINCE EDWARD GIVES UPDATE ON PRINCE PHILIP'S HEALTH AMID HOSPITALIZATION

Police officers stand at an entrance to the King Edward VII Hospital where Prince Philip is being treated for an infection, as an ambulance is driven out, in London, Monday, March 1, 2021. (AP Photo/Frank Augstein)

The palace says Philip "remains comfortable and is responding to treatment but is expected to remain in hospital until at least the end of the week.’’

Philip’s illness is not believed to be related to COVID-19. Both he and the queen, 94, received a first dose of a coronavirus vaccine in early January.

Philip, who retired from royal duties in 2017, rarely appears in public. During England’s current coronavirus lockdown, Philip, also known as the Duke of Edinburgh, has been staying at Windsor Castle, west of London, with the queen.

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Philip married the then-Princess Elizabeth in 1947 and is the longest-serving royal consort in British history. He and the queen have four children, eight grandchildren and nine great-grandchildren.

The Associated Press contributed to this report.