Michael Schumacher, the seven-time Formula 1 champion, is in a critical condition after a skiing accident, says the French hospital treating him.
The 44-year-old German suffered serious brain trauma, was in a coma on arrival and underwent immediate surgery.
He was skiing off-piste with his son in the French Alps on Sunday morning when the accident occurred.
The hospital in Grenoble will issue further information on his condition at 11:00 local time (10:00 GMT).
Schumacher was wearing a helmet when he fell and hit his head against a rock, his manager Sabine Kehm said.
Reports in French and German media say that the F1 legend underwent a second operation during the night.
Germany's Bild tabloid reported that his condition had worsened and surgeons had drilled holes in his skull to reduce the pressure on his brain.
Early reports had said his condition was not life-threatening and he reportedly walked away from the accident complaining only of feeling a bit shaken.
The accident took place in the French ski resort of Meribel.
The resort's director, Christophe Gernignon-Lecomte, said the former champion was attended to by two ski patrollers who requested helicopter evacuation to the nearby valley town of Moutiers.
He was subsequently moved to the bigger facility at Grenoble, in south-east France. His wife Corinna and two children are with him.
'Critical situation'
"Mr Schumacher was admitted to the University Hospital of Grenoble at 12:40 [11:40 GMT], following a skiing accident which occurred in Meribel in the late morning," the Grenoble hospital said in a statement.
"He suffered a severe head injury with coma on arrival, which required immediate neurosurgical intervention. He remains in a critical situation."
The hospital statement was signed by the facility's neurosurgeon, the professor in charge of its anaesthesia/revival unit, and the hospital's deputy director, reports said.
Experts say it is likely that his brain began to swell and the urgent surgery was required to relieve the pressure, says the BBC's Hugh Schofield in Paris.
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Michael Schumacher
*Born: 3 January 1969
*First GP win: Belgium 1992
*Last GP win: China 2006
*Races started: 303
*Wins: 91 (155 podium finishes)
*Championships: 7 (1994, 1995, 2000, 2001, 2002, 2003, 2004)
*Born: 3 January 1969
*First GP win: Belgium 1992
*Last GP win: China 2006
*Races started: 303
*Wins: 91 (155 podium finishes)
*Championships: 7 (1994, 1995, 2000, 2001, 2002, 2003, 2004)
