Michael Schumacher, the retired seven-time Formula One champion, was still in a "critical condition" on Monday after suffering severe brain trauma in a skiing accident in the French Alps, doctors said.
The German racing legend, who turns 45 at the end of the week, had been skiing off-piste Sunday with his 14-year-old son in the upmarket Meribel resort when he fell and hit his head on a rock.
Doctors at the hospital in the southeastern city of Grenoble where he is being treated said it was still too early to make a prognosis on the famous patient.
"We can not comment on the future of Michael Schumacher," said Jean -François Payen, head of the intensive care unit, told reporters.
"He is in critical condition. He is in intensive care, his condition is very serious," said Payen. "We are working hour by hour," he said, adding that for the moment no further surgery was planned for Schumacher.
Stephan Chabardes, the professor who operated on Schumacher, said the former racer arrived in hospital on Sunday in an agitated state and was not able to answer questions.
His condition "rapidly deteriorated" and he fell into a coma, he told reporters. Doctors said the aim was to reduce pressure around the brain and that his temperature was being maintained between 34 and 35°C in line with international guidelines.
Payen said he was operated on and put into an artificial coma, adding he had been partially protected by his helmet.
"If someone had had this type of accident without a helmet, they would definitely not be here," he said.
(Photo: Jose Jordan/AFP)
According to research carried out by Austria's University of Innsbruck, helmets reduce head injuries to adults by 35% and to children under 13 by 59%,
Doctors said further updates would be given if the situation changed.
News of the accident stunned the Formula One community and racing stars joined German Chancellor Angela Merkel and legions of fans in wishing him a speedy recovery.
In a statement released later Monday, Schumacher's wife Corinna and the rest of his family thanked well-wishers and gave a special nod to the doctors treating him.
"We would like to thank the medical team who, we know, do everything possible to help Michael," Corinna said in a statement.
A renowned Parisian neurologist, doctor Gerard Saillant, was flown to the Grenoble hospital in a police car to help take charge of the famous patient.
Schumacher's wife Corinna was at his side with his two children, the hospital said.
Schumacher a 'crazy daredevil'
News of Schumacher's accident stunned the Formula One community and his former teammates joined thousands on Twitter in wishing him a speedy recovery.
"My thoughts are with Michael Schumacher at this tough time.. Michael more than anyone has the strength to pull through this," tweeted British F1 driver Jenson Button.
Schumacher's former teammate at Benetton Martin Brundle wrote on Twitter: "Come on Michael, give us one of those race stints at pure qualifying pace to win through, like you used to. You can do it."
He added that the German was "a crazy brave skydiving/bike racing daredevil".
Brazilian Formula One racing driver Felipe Massa said he was "praying for God to protect you my brother!! I wish you a speedy recovery Michael", the former Ferrari driver wrote.
The next update on Schumacher's condition would be given at 1000 GMT on Monday, a hospital spokesman said.
Police kept guard at the hospital's entrances as journalists and fans, some wearing the colours of the Formula One legend's former stable Ferrari, gathered outside awaiting news of his health.
Police have opened an investigation into the circumstances of the accident, the ski resort said.
Schumacher, who won the last of his world titles in 2004, definitively retired in 2012 in the Brazilian Grand Prix, in which he finished seventh, after an abandoned attempt to quit six years earlier.
Since his debut in 1991, the German towered over the sport, winning more Formula One world titles and races than any other. He had a record 91 wins and is one of only two men to reach 300 grands prix.