Britain's Prince Philip is likely to remain in hospital until next week, a royal source was cited by media as saying on Friday, adding that doctors were acting "out of an abundance of caution" and that the Duke of Edinburgh remains in good spirits.
"Following consultation with his doctor The Duke of Edinburgh is likely to remain in hospital for observation and rest over the weekend and into next week," the source said.
Queen Elizabeth's 99-year-old husband was admitted to King Edward VII Hospital in central London after feeling unwell because of an unspecified ailment, with his condition being reportedly unrelated to the coronavirus. The Queen, 94, took part in her first face-to-face event of the year on Thursday as she knighted a royal aide.
Vice-Admiral Sir Tony Johnstone-Burt, a former Royal Navy officer, was created Knight Commander of the Royal Victorian Order during a private socially distanced ceremony. The rest of the royal family, including the Prince of Wales and the Duchess of Cornwall, also continued with their official duties this week.
Both the Duke of Edinburgh and the Queen received their first dose of the COVID-19 vaccine back in January.
As coronavirus swept across the UK, the couple retired first to Windsor Castle, in Berkshire, as a precaution because of their age. They then spent time at the royal residences of Balmoral, northeast Scotland, and Sandringham, in East Anglia, before returning to Windsor in October.