(see related) Rome, April 8 - Ambulance crews were forced to flee after their vehicle was pelted with sticks, stones and firecrackers Monday during clashes between soccer fans in the area around Rome's Olympic Stadium before a high-profile match between hometown rivals Roma and Lazio. Some store owners closed up shop early and smoke bombs were thrown on neighbourhood streets as police tried to break up fights among fans on opposing sides of a soccer match scheduled in the evening. Even some motorists stuck in traffic on streets in the area were drawn into the melee. At least two people sustained minor injuries. Speaking from the area near the Milvian Bridge, Rome's Mayor Gianni Alemanno said he was "very concerned" and called for calm.