Sheffield-born IndyCar driver Justin Wilson is in a coma after being hit by a piece of debris during Sunday's race in Pocono.
The 37-year-old former Formula One driver, who currently competes for Andretti Autosport, suffered a head injury when Sage Karam's car crashed in front of him, and he was soon airlifted to hospital by helicopter.
A statement published on indycar.com read: "IndyCar driver Justin Wilson suffered a severe head injury during today's event at Pocono Raceway.
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"Wilson is currently in a coma and in critical condition while undergoing further evaluation at Lehigh Valley Health Network in Allentown, Pennsylvania.
"IndyCar sends its thoughts and prayers to Justin, his family, and Andretti Autosport during this difficult time.
"Additional updates to Wilson's condition will be released when available."
Wilson is a former F1 driver having competed for Minardi and Jaguar during the 2003 season.
His younger brother Stefan, also an IndyCar driver, tweeted a message of support on Sunday night, writing: " Praying for my bro right now. Trying to get myself and Julia, JWs wife to Pocono. Thank you for prayers and thoughts at this very hard time.
"I have no update on his condition, he's been moved to the local hospital, and I'm trying to get there to be with him. Please don't speculate"
Wilson's crash comes almost four years after British driver Dan Wheldon was killed at the Las Vegas Speedway in the same series.