A dusty plateau on Lima's southern outskirts with a protected pre-Incan burial site has become a scene of violent clashes between Peruvians desperate for land and a new police unit tasked with dislodging squatters.

Hundreds of police used tear gas and clubs Tuesday to remove about 2,000 squatters.

Squatters hurled rocks at shield-wielding police. Many officers responded by throwing them back. Police reported three injuries in their ranks and 11 arrests. There was no word on civilian injuries.

Police reported 164 land invasions last year in Lima, a city of nearly 10 million. A special unit to battle them was formed in 2013. Lima adds about 150,000 people per year.

A Culture Ministry official said about three dozen pre-Inca tombs were found where Wednesday's clash occurred.