Nicky Hayden, a former MotoGP champion who suffered a serious bicycle accident last week, has died, the Italian hospital where he was admitted said Monday.
"Doctors established the death of the patient," the Bufalini hospital of Cesena said in a statement.
Hayden, 35, was run over by a car on Wednesday while riding a bicycle near the beach town of Riccione, three days after racing in Italy's Imola track for the Superbike World Championship.
He has been in intensive care since, with doctors reporting Thursday that he had "suffered a severe poly-trauma, resulting in very serious brain damage."
His death has been followed by an outpouring of tributes on social media.
US-born Hayden is known in the sport as The Kentucky Kid. He won the MotoGP championship in 2006 and has been competing for Team Honda in the Superbike category since last year.