04/08/2013 04:02 EDT | Updated 06/08/2013 05:12 EDT

4 fans stabbed before Roma-Lazio derby, ambulance abandoned after attack by fans

ROME - At least four fans have been stabbed and an ambulance attacked in clashes ahead of the Rome derby between Roma and Lazio.

The ANSA news agency reports an ambulance was abandoned after fireworks, rocks and sticks were thrown at it Monday.

After hearing of the news, Rome Mayor Gianni Alemanno made an appeal for calm ahead of the match Monday night.

There is a heavy police presence around the Stadio Olimpico and nearby stores closed early ahead of the night game.