MILAN, Italy (AP) - Police fired tear gas bombs into a crowd of 1,000 stone-throwing youths who tried to break into a tent-theatre for a performance of Canadian singer Joni Mitchell, police said Tuesday.

Several youths and policemen were injured, none seriously, in the nearly three-hour melee Monday night on the outskirts of Milan, police said.

One car was set afire and others were damaged, and dozens of youths were taken into custody and released after identification.

Traffic in the area, near the Milan hippodrome, was blocked for hours, delaying ambulances carrying the injured to the hospitals.

Inside the theatre, the Canadian star completed her concert for an audience of 7,000 people. It was not known whether she was aware of the trouble outside.