MEXICO CITY (AP) — State police in central Mexico said 11 officers were injured by student protesters Friday, while video circulated on social media showing a police bus hitting and knocking over at least one demonstrator.

Michoacan state Public Safety Secretary Israel Patrón said students from a local teachers’ college blocked a road and then attacked officers using fireworks, stones and sticks. Police tried to stop them and a confrontation ensued, he said.

Video images posted on the college’s social media page showed a chaotic scene in which detonations can be heard and clouds of smoke or gas are seen.

Dozens of protesters are running in the road when a bus with blue-and-white state police markings appears, makes a sudden U-turn and knocks over a protester before escaping.

Patrón said that was not “an intentional attack” by police. “It was done by the bus driver while he was engaged in a struggle with two students who were trying to take over the bus,” he said.

The official said one student suffered an injury to his leg, was treated and released.

Police officers put out a fire after a clash with students involved in campus takeovers in Tiripetío, Michoacan state, Mexico, Monday, Oct. 15, 2012. Police raided three teachers colleges on Monday in the western state of Michoacan, where dozens of students had been hijacking buses and delivery trucks for a week to protest curriculum changes. (AP Photo)

The rural teachers’ college in the Michoacan town of Tiripetío trains mainly working class youths to be teachers in remote communities.

While the school is government funded, students complain of a chronic lack of resources. The school promotes a leftist ideology and its students have frequently clashed with police in the past, and have often seized private trucks and buses to enforce their demands.