MTV says it warns viewers not to copy the stunts

The fire grew out of control and burned the boy's legs and hands before it was extinguished, officials said after the incident on Friday.

Jason is in a critical condition in the burns unit of Shriner's Hospital for Children in Boston.

His 14-year-old friend - who is not being named by police - was arrested on Saturday and charged with reckless endangerment.

The MTV programme, which shows an array of pranks and stunts, was also criticised by Connecticut senator Joseph Lieberman, Al Gore's running-mate in last year's presidential elections and a critic of media violence.

"MTV is an enormously influential force in the world our children inhabit, and with that power and the right to exercise it comes a certain level of responsibility," he said.

Disclaimers

"I intend to make clear to the network's owners that we expect more from them."

One of the teenagers said Jason volunteered to re-enact the stunt, which took place in one boy's back yard.

MTV spokeswoman Tina Exarhos said the show includes written and verbal disclaimers stating: "The following show features stunts performed by professionals and/or total idiots under very strict control."

The producers "insist that neither you or anyone else attempt to recreate or perform anything you have seen", the warning states.

Ms Exarhos said the warning is repeated by Knoxville.

Another teenager who looked during the incident on was not charged.