Demonstrators have clashed with police in Chile's capital, Santiago, leaving a 15-year-old girl seriously injured and dozens more under arrest in protests that coincided with the 38th anniversary of the country's military coup.

Authorities say the disturbances began Saturday and continued well into Sunday and that 280 people were arrested. Forty police officers were injured. Officials say protesters also set fires. Electricity was cut to 130,000 homes.

The unrest follows protests against the policies of President Sebastian Pinera's conservative government. Recently, demonstrations were held to call for education and tax reform, and constitutional change.

The trouble over the last two days coincided with the anniversary of the September 11, 1973 coup that toppled the elected government of President Salvador Allende and brought dictator General Augusto Pinochet to power. General Pinochet ruled Chile until 1990.

His poor health over the years exempted him from standing trial for the deaths or disappearances of more than 3,000 people during his 17-year rule. He died in 2006.