Former Formula One driver, CART champion, and Paralympian Alex Zanardi was critically injured Friday, according to multiple media reports.

Various reports say Zanardi was training for a race or riding in a relay stage of the handbike Obiettivo Tricolore race.

The two-time CART champ's legs were amputated after a 2001 crash at Germany's Lausitzring. Zanardi, who is 53, returned to car racing and became a competitive handbike racer, winning multiple medals at the 2012 and 2016 Summer Paralympic games.

News reports say Zanardi was involved in a crash with a "heavy vehicle" at 5:05 pm near Siena, Italy.

Alex Zanardi at the Lausitzring

Alex Zanardi at the Lausitzring

Zanardi was airlifted to Siena University Hospital for treatment.

In a statement the hospital said Zanardi "was immediately taken care of by the emergency room professionals, assessed in the shock room and his conditions are very serious due to the severe head injury and is currently undergoing a delicate neurosurgery."