Philip, who turns 92 on Monday, was said to be in a “comfortable” condition on Friday night after having an exploratory operation at the private London Clinic earlier in the day.
Details of the original symptoms that prompted the operation have not been released by Buckingham Palace, but it is thought the procedure did not involve the Duke‘s heart or bladder, where he has experienced problems before.
Analysis of the results of the operation are expected to be completed next week.
In a statement on Friday night, Buckingham Palace said: “His Royal Highness the Duke of Edinburgh has had an exploratory operation following abdominal investigations. The results will now be analysed.
“At this early stage he is progressing satisfactorily. Further updates will continue to be issued when appropriate.”
The Duke could stay in hospital for up to two weeks while he recovers from the operation.
The Queen has been kept fully informed of her husband’s progress and is spending the weekend as planned at Windsor Castle.
He’s one of those people who wouldn’t want you to stop just because he’s gone into hospital.Peter Phillips
On Friday, as she opened the BBC’s revamped Broadcasting House headquarters in London, Radio 4 presenter John Humphrys suggested that Philip had looked well during his appearance at a garden party on Thursday and the Queen told him: “That’s because he’s not ill.”
Peter Phillips, the Duke’s eldest grandson, said: “Obviously our thoughts and prayers are with him, we know that he’s in good hands and we’ve been kept up to date in terms of what’s happening.
“But he’s one of those people who wouldn’t want you to stop just because he’s gone into hospital.”