CNN  — 

Ex-Formula One driver and four-time Paralympic gold medalist Alex Zanardi remains in an artificial coma after suffering severe head injuries in a horrific cycling race crash.

The 53-year-old Zanardi, who had both his legs amputated after a motor racing accident almost 20 years ago, lost control of his handbike machine while competing in the ‘Obiettivo tricolore’ relay race in Tuscany, Italy on Friday.

According to multiple reports, he crossed the white line into the path of an oncoming truck, which was unable to avoid him.

Following the accident, the Italian was airlifted to the Santa Maria alle Scotte hospital in Siena where he underwent three hours of emergency neurological surgery for facial head injuries.

READ: The fairytale of Alex Zanardi continues at Rio Olympics

The hospital released an updated medical bulletin on Sunday, saying Zanardi’s condition remains “serious” but stable.

“The current conditions of general stability still do not allow to exclude the possibility of adverse events,” it added.

Zanardi’s plight was captured in the headlines of all the major Italian sports papers as news spread of the seriousness of his accident.

“No Alex, no!” said Corrierre dello Sport, while Italian prime minister Giusseppe Conte wrote on Twitter: “Come on Alex # Zanardi, don’t give up. All of Italy is fighting with you.”

Zanardi raced for Jordan, Minardi and Lotus in F1 before a successful switch to CART racing in the US where he was series champion in 1997 and 1998.

He returned to F1 with Williams for one season in 1999 before returning to the CART series.

It was in that formula that he suffered his infamous 320kmh crash at Lausitzring in Germany in September 2001, escaping with his life, but losing both his legs.

In an incredible show of determination and spirit, Zanardi adapted to his prosthetic legs and returned to compete in the European Touring Car Championship in 2003, driving for BMW.

But it was for his exploits on a handbike that the man from Bologna has become best known to a worldwide audience, winning multiple medals at the 2012 and 2016 Paralympics and world championships.

He was in training for this year’s Tokyo Paralympics, hoping to add to his impressive tally of gold medals, until it was postponed.

Zanardi has also competed in grueling Ironman triathlon races, setting a new world best for a Paralympic athlete at a race in Italy last September as well as continuing to race specially-adapted BMWs in various endurance motorsport events.

Messages of support have come flooding in across the sporting world, with former F1 world champion and Indy Car legend Mario Andretti writing: “I am so anxious and frightened about Alex Zanardi that I’m holding my breath. I am his fan. I am his friend.

“Please do what I’m doing and pray, pray for for this wonderful man,” he tweeted.

“Alex is one of life’s truly inspirational people and as we all know, a fighter through and through. Stay strong and Forza Alex,” his former Williams team posted on Twitter.

“Fight as you know how to do it, Alex. You are a very great man, courage,” Ferrari star Charles Leclerc tweeted in Italian.