MILAN, Italy (AP)---Fifteen Joni Mitchell fans were sentenced to six months each in jail after being convicted of throwing rocks and petrol bombs at police during her concert here.

A local court heard that about 1,000 fans went on the rampage after they were unable to buy tickets for a sold-out concert by Miss Mitchell in this northern Italian city May 9.

The furious fans tried to get into the concert without paying, the court heard. Police responded with tear gas and arrests and 37 police officers were injured in the clashes.

Two other defendants were cleared in the trial.