The owners of Camelot, the Epsom Derby winner, have confirmed that the three-year-old has had exploratory surgery for colic.
Coolmore Stud announced that Camelot was taken to a veterinary hospital in County Tipperary but the outcome of the operation is unknown.
A statement posted on Twitter said: "Obviously it's still very early days but a further bulletin will be released in the morning."
Despite Camelot's impressive early season form, Frankie Dettori rode the Aidan O'Brien-trained horse to a seventh-place finish in the Prix de l'Arc de Triomphe at Longchamp on Sunday.
