MotoGP riders have shown their support for Nicky Hayden, who remains in an "extremely serious" condition following Wednesday's cycling accident in Italy.
The American, who won the title in 2006, was struck by a car while training on a bicycle along the Rimini coast and admitted to a local hospital, before being moved to the Maurizio Bufalini Hospital in Cesena.
On Friday the hospital provided an update on the Honda World Superbike rider's status, as several MotoGP competitors bore symbols and hashtags in tribute to the 35-year-old.
"The clinical conditions of Nicky Hayden, hospitalized on Wednesday, May 17, remain extremely serious in the hospital resuscitation department of the Bufalini hospital in Cesena," a statement read.
"The young rider reported a severe polytrauma resulting in severe brain damage.
"The prognosis remains confidential."
Hayden competed in the Italian round of the Superbike World Championship at Imola last weekend.
He has 218 MotoGP races under his belt and won the world title with Repsol Honda 11 years ago – ending Valentino Rossi's streak of five successive championship victories – and also raced for Ducati before switching to the Superbike circuit last year.