The eminent US film critic Roger Ebert has refused to apologise for anti drink drive comments made on Twitter following the death of Jackass star Ryan Dunn on Monday.

Dunn and another passenger died when the car they were travelling in – Dunn's Porsche 911 – hit a tree and burst into flames in West Goshen, Pennsylvania. The 34-year-old, who was driving the vehicle, had appeared in all three Jackass films, along with three seasons of the MTV TV show which spawned them.

A few hours before the accident, Dunn had tweeted pictures of himself drinking with friends to his followers. Ebert later commented: "Friends don't let Jackasses drink and drive" via Twitter, spawning an immediate backlash from some of his followers. The celebrity blogger Perez Hilton was one of the first to suggest that the film critic's comments may have been made too soon after Dunn's death, but Ebert later tweeted in response: "Perez Hilton's readers agree with me and not with Perez about my tweet on Ryan Dunn. He drank, he drove, 2 people died."

Dunn was identified by his tattoos, according to a witness who was on the scene when the bodies were pulled from the wreckage. The mother of Dunn's Jackass co-star Bam Margera reportedly called a local radio station to confirm that he was killed in a car accident.

Dunn's Jackass costar Johnny Knoxville tweeted: "Today I lost my brother Ryan Dunn. My heart goes out to his family and his beloved Angie. RIP Ryan, I love you buddy."

A preliminary police report from the West Goshen police department cited speed as a possible contributory factor in the deaths of Dunn and his friend, but did not mention alcohol.

Dunn had been about to start shooting a new TV show for the US G4 network, Proving Ground. The aim was to show the outcome of undertaking film and video game stunts in the real world. "All of us at G4 are shocked and deeply saddened by the tragic news that Ryan Dunn has passed away," the network said in a statement confirming that the show was being put on hold. "Ryan's comedic wit and signature no-holds-barred approach made him an incredible talent and his work as host of G4's Proving Ground was flawless. Ryan will be missed dearly by his legion of fans and we extend our heartfelt condolences to his family and friends during this difficult time."