Two fans in critical condition after loud sound spreads panic among thousands gathered to watch Champions League final.

Up to 1,400 people were injured in the Italian city of Turin at a stampede during a public screening of the Champions League final, local media reported on Sunday quoting emergency services.

Around 30,000 people were watching the match on Saturday between Turin side Juventus and Real Madrid at the city’s Piazza San Carlo when fans began running away in panic.

Turin’s police chief said the stampede may have been triggered by someone letting off a firework, with people mistaking it for a bomb. Local newspaper La Stampa also reported that a collapsed barrier could have led to the panic

At least eight people were seriously injured. A seven-year-old boy and a woman were reported to be in a critical condition. Most of the other injuries were believed to be minor.

The square was evacuated so quickly it was left strewn with hundreds of sneakers ripped off people’s feet as they ran, officials said.

Most of the Juventus fans suffered minor injuries [Giorgio Perottino/Reuters]

The incident compounded a sorrowful night for supporters of Juventus, who lost the Cardiff final 4-1 to Real Madrid.

Video cameras showed a sudden rush in the middle of the crowd that caused a surge that flung people against barriers. Some of the injuries occurred after a railing around the entrance to an underground parking beneath the square gave way under the weight of the crush, officials said.

Afterwards shoes and bags littered the ground, people were seen limping and searching desperately for friends and relatives.

Police said they are investigating what caused the panic and an information line has been set up to help people find their loved ones.

A similar incident happened in 1985 in Heysel stadium in Belgium, in which 39 mostly Italians and Juventus fans were killed and 600 were injured after being crushed by a collapsing wall before the start of that year’s European Cup final, against Liverpool.