Dual Derby winner Camelot has undergone exploratory colic surgery, Coolmore have said.
The colt, who just failed to become the first Triple Crown winner in more than 40 years at Doncaster last month, has been admitted to Fethard Veterinary Hospital in Ireland.
Camelot ran in the Prix de l'Arc de Triomphe at Longchamp on Sunday where he finished seventh on very soft ground.
"Triple Classic winner Camelot was admitted to Fethard Veterinary Hospital this evening and underwent exploratory colic surgery," a tweet from Coolmore Stud said on Thursday.
Coolmore said it would issue further updates on Camelot's condition when more was known.