SANTIAGO - Thousands of middle-school students clashed with police Thursday in and around the Chilean capital Santiago as students took part in demonstrations that were not authorized by the government, local media reported.

In the capital's Alameda Avenue, near the University of Chile in downtown Santiago, protesters threw rocks and stones at riot police who countered with tear gas and water cannons. So far, no injuries have been reported.

In the suburb of Providencia, just outside the city, police and students clashed after students refused to obey orders to disperse.

Press reports placed the number of students marching through Alameda Avenue at thousands, saying they blocked streets before clashing with riot police.

Late Thursday afternoon, several main streets in downtown Santiago remained closed to traffic and stores were shuttered, though press reports said the demonstration sites had been cleared and arrests had been made, though there was no official confirmation regarding the number of students detained.

Students have been protesting since 2011 to demand free and quality public education, and ask for local control of schools by district heads or city mayors, as opposed to the Education Ministry.