By Agence France-Presse

A Nobel Peace laureate added her voice Monday to calls for Chile to stop police violence against protesters during recent weeks of deadly anti-government unrest.

Protests against economic hardship have erupted into vandalism, looting and clashes between demonstrators and police, leaving 20 dead.

Prosecutors say five of those people died at the hands of state agents. A UN human rights mission is investigating allegations of police brutality.

On Monday, the 1992 Nobel Peace Laureate, Rigoberta Menchu of Guatemala, led other activists in delivering a letter at the presidential palace urging an end to what they called “serious and systematic” abuses.

They called on Chile’s President Sebastian Pinera to “immediately halt the violence” by security forces.

Chile’s independent National Human Rights Institute says it has brought legal action over 179 cases including alleged murders, sexual violence and torture by the military police.

The institute’s director, Sergio Micco, denied that the abuses constituted a systematic government policy, however.

The institute says 1,574 people have been hurt in the unrest.

“Terrible acts of repression have been carried out by members of the security forces and other state agents,” said the letter, read out by activist Guillermo Whpei.

Menchu backed protesters’ calls for constitutional reform in Chile. The current constitution dates back to the 1973-1990 dictatorship of Augusto Pinochet.