Former MotoGP world champion Nicky Hayden remained in an "extremely serious" condition in hospital on Thursday, having been hit by a car while cycling the previous day.
Hayden, who is in his second season with the Red Bull Honda World Superbike Team, was initially taken to a local hospital in Rimini following the incident.
However, the 35-year-old American was subsequently transferred to the Bufalini Hospital in Cesena.
A statement from the hospital on Wednesday night confirmed Hayden was in a critical condition in intensive care, adding: "Because of his injuries it was not possible to perform surgery."
On Thursday, an update quoted by La Gazzetta dello Sport read: "There are no substantial changes from what was communicated yesterday evening. Nicky Hayden remains hospitalised in the intensive care unit. The clinical picture remains extremely serious."
Hayden was cycling along the Rimini coastline when the accident took place, having raced in the Italian round of the Superbike World Championship at Imola last weekend.
A veteran of 218 MotoGP races, he won the world title with Repsol Honda in 2006 - ending Valentino Rossi's streak of five successive championship victories - and also raced for Ducati before switching to the Superbike circuit last year.
News of his accident sparked a flood of tributes from fellow riders on social media, with reigning MotoGP world champion Marc Marquez among those to offer messages of support.