Fans converged on the Grenoble hospital on Friday to honor the Formula One champion on his 45th birthday, just days after he was injured in a skiing accident in the French Alps.

Busloads of fans from France and Italy arrived early in the morning to pay tribute to the racing driver, who has been placed in an artificial coma.

Guilo Carission told the Associated Press news agency that he had driven for hours to reach Grenoble. Wearing a Formula One Ferrari jacket and hat he said he felt compelled to come.

"With all the joy he has given us with his victories, we had to be there," he added.

Ferrari, for whom he raced, sent their best wishes to Schumacher via a statement issued on their website.

"At the moment, he is tackling the most important fight of his life and therefore we want to send him very special wishes," the team said.

Schumacher has been treated at the Grenoble hospital since he fell and hit his head on a rock while skiing off-piste at the Meribel ski resort on Sunday.

There has been no official update of his condition since Wednesday, when his long-time manager Sabine Kehm told reporters he was critical but stable. Like the doctors treating Schumacher, however, Kehm refused to comment on his chances of recovery.

"Michael is being monitored around the clock, the doctors are taking very good care of him," she said.

Schumacher: 'a fighter'

There has been a huge public outpouring of sympathy for Schumacher's plight from fans and famous personalities alike.

His family has responded to the well-wishers from all over the world with an open message.

"Following Michael's skiing accident, we would like to thank the people from all around the world who have expressed their sympathy and sent their best wishes for his recovery," the family wrote.

"We all know he is a fighter and will not give up," they added.

The driver's wife Corinna, and their two children were at his bedside again on Thursday, alongside close friends and associates, including Jean Todt, his former boss at the Ferrari team.

Ross Brawn, Schumacher's boss at his last team, Mercedes-AMG, from which he retired from racing in 2012, arrived in Grenoble on Sunday night. Neither has spoken to the press.

Schumacher has been in a coma since doctors conducted two operations to remove bleeding and relieve pressure on his brain which developed as a result of the accident. He was wearing a helmet when he fell, but a source close to the investigation into the cause of the accident said the impact was so great that it caused the helmet to split into two.

Schumacher was Formula One's most successful driver of all time, having won 91 Grand Prix races and seven drivers' championships over a career that spanned most of two decades.

jlw, ccp/tj (AFP, dpa, SID)