Shocking footage shows a man appearing to throw a gas cylinder from the balcony at police and crowds.
Tension arose at dawn when police arrived in Piazza Indipendenza, Rome to empty a building that had been allegedly illegally occupied.
During the operation, officers were met with violent resistance from the migrants.
Stones were thrown at them and a short street fight ensued.
Two people were arrested.
Police were forced to use fire hydrants to avoid fires and flammable liquids being set on fire.
The Rome Police headquarters clarified that the intervention had become necessary after the group of migrants refused to leave the building.
The migrants have been forced to move because of reported presence of dangerous gas cylinders and incendiary devices in the occupied building.
A woman was hurt during the clash but Doctors without Borders members on the scene intervened to offer assistance.
The migrants involved in the accident have been processed in a local police station and moved to alternative lodging.
Tension has been growing in Italy over the high number of migrant arriving on Southern seaports from the North African coast.