More than 1,500 people were injured when panic swept through a crowd of Juventus fans watching the Champions League football final in a piazza in the northern Italian city of Turin. Authorities said this today.The Turin prefect said in a statement that the crowd was taken by panic and by the psychosis of a terror attack, fearing that a loud noise was caused by attackers. Officials said that the source of the loud noise that triggered the stampede remained unclear. Italian media has speculated it may have been a firecracker.The noise triggered panic among thousands of fans gathered in Piazza San Carlo to watch the match pitting Juventus against Real Madrid on giant TV screens. Fans were trampled as they tried to flee. Among the injured, three including a young boy, were in serious condition, officials said.