Ferrari fans from France, Italy and Germany are reflected in a puddle of water as they attend a silent 45th birthday tribute to seven-times former Formula One world champion Michael Schumacher in front of the CHU hospital emergency unit in Grenoble, French Alps, where Michael Schumacher is hospitalized January 3, 2014. His agent said on Wednesday that Michael Schumacher was in a stable condition and it was too early to talk about his further prospects. No further update was given on Thursday, the day before his 45th birthday. Schumacher is battling for his life after slamming his head against a rock while skiing off-piste in the French resort of Meribel on Sunday. REUTERS/Emmanuel Foudrot (FRANCE - Tags: SPORT MOTORSPORT HEALTH)

Fans of Michael Schumacher gathered on Friday for a silent vigil for the Formula One legend's 45th birthday as he lay in a coma in a French hospital after a weekend skiing accident.

Ferrari bussed in scores of fans from Italy and France to the hospital in the Alpine city of Grenoble and put a special message on its website, saying “Forza Michael,” or “Go Michael” in Italian.

“He is tackling the most important fight of his life and therefore we want to send him very special wishes,” said Schumacher's old team, as similar messages poured in from around the world.

Former tennis ace Boris Becker wished his compatriot “Happy Birthday” on Twitter, adding “Fight Schumi” in a German hashtag.

The retired seven-times world champion fell and slammed his head against a rock on Sunday morning while skiing in the French Alps and has had two operations to remove bleeding and pressure on his brain.

The accident shocked legions of fans used to seeing Schumacher cheat death on the race track.

He is being kept in an induced coma and in the latest health update given by his manager on Wednesday, his condition was described as stable but still critical.

His family is at his side, including his wife Corinna, his two teenage children, his father Rolf and brother Ralph, who is also a racing driver.

The family said in a post on Schumacher’s website: “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.”

“We all know he is a fighter and will not give up.”

Fans left a poster outside the Grenoble hospital saying “Schumi, All our Thoughts for You and Your Family.”

Stefano Pini, 47 an accountant who arrived from Milan to pay tribute, said: “Schumi has given us a lot in the past.

“The least we could do is to come here and support him and his family on his birthday.”

French fan Gabriel Klose, who turned up with his 12-year-old son, said: “He is one of my greatest idols. We want him to fight and to return to us.”

However, the Ferrari tribute has created controversy with some accusing the Italian racing giant - which asked fans to sport its trademark colour red and its insignia - of exceeding the limits of good taste.

The carmaker, which has 130 clubs in Europe, provided about 20 coaches across Italy to bus in fans for the vigil.

But Roberto Luongo, president of the Roma-Colesseo Ferrari club, said he did not want to be associated with an event linked to “a man who is suffering”.

“It's very delicate and if I was among those who are close to Michael, such an initiative would not have pleased me,” he said.

Schumacher's fan club in his childhood town of Kerpen said any celebration of the birthday would be in bad taste.

There have been conflicting statements about the speed Schumacher was going when he crashed in the upmarket Meribel ski resort, where he has a holiday home.

The impact as he hit a rock reportedly split his helmet in two.

The hospital and Schumacher's manager had briefed the press daily since the accident but on Thursday they said they would communicate only if there was something new to report.

His manager Sabine Kehm said Wednesday that Schumacher was stable though still critical.

The hospital has faced frenzied media and public interest in its famous patient and a vacant lot nearby has been turned into an impromptu parking area for television satellite vans.

Kehm said earlier this week that some people had tried to sneak into Schumacher's room, one dressed as a priest.

Questions have emerged over exactly how the accident happened on a small, seemingly innocuous off-piste section of Meribel located between two ski slopes - one classed as easy and the other as intermediate.

Investigators are looking at whether the limits of the pistes next to the accident site were correctly marked, and whether the safety releases on Schumacher's rented skis were working properly. - AFP