ELMONT - Authorities say two horses died this morning in a training accident at Belmont Park.

One of the horses, Caixa Eletronica, a 23-time winner, collided with another horse named Six Drivers, who was running loose at the time, officials say.

Caixa Eletronica suffered a fractured skull and Six Drivers suffered a neck fracture. Both horses were killed instantly, officials say.

Caixa Eletronica had won seven stakes, including the 2011 Grade 3 Westchester, 2012 Grade 2 Charles Town Classic, 2012 Grade 2 True North Handicap, and 2012 Grade 3 Fall Highweight Handicap.

Long Island native and owner of Caixa Electronica Mike Repole called it a "terrible day for racing."

Caixa Eletronica's rider, Carlos Castro, was taken to North Shore University Hospital with unspecified injuries.