The demonstrators tried to get closer to Via Alessandria, where the school is located, but were blocked by police with tear gas and the use of hydrants, Presstv Reported.
The demonstrators threw stones and big firecrackers and set fire to bins. A bus was also attacked.
"They were all masked. They banged with sticks and threw in things. I could not breath anymore. I had to run away," the driver recalled.