VERONA, Italy - Olympic show jumping champion Eric Lamaze's horse Hickstead died during a World Cup event Sunday, after collapsing to the ground and writhing in pain inside a packed arena.

The Canadian partnership had just completed the 13-fence course with a single rail down in the middle of the combination when the horse fell ill, the International Equestrian Federation said.

"As yet the cause of death is unknown, but our deepest sympathies go out to the owners, to Eric and to all the connections of one of the greatest jumping horses of all time," said FEI jumping director John Roche. "Hickstead's presence on the circuit will be very sadly missed."

Veterinarians attempted to revive the horse to no avail and it was carried out of the ring dead as stunned fans at the Rolex FEI event looked on.

The competition was then abandoned at the request of the riders, and Lamaze's fellow competitors gathered for a minute's silence.

The Schomberg, Ont., rider won individual gold and team silver aboard Hickstead at the 2008 Beijing Olympics.

"Hickstead really was a horse in a million and my heart goes out to Eric and everyone connected with this wonderful horse," said FEI president Princess Haya. "This is a terrible loss, but Hickstead truly will never be forgotten. We were very lucky to have known him."