Chilean hunger strike activist Patricia Troncoso is at serious risk of death after 100 days without food, a doctor monitoring Troncoso said Sunday.

"She is in a very, very serious condition," Berna Castro from the medical team said of Troncoso, who is hospitalized in southern Chilean city of Chillan.

Troncoso is protesting against a 10-year prison sentence relating to an arson of forest land.

"Troncoso could die at any moment. She is at stage three: the most serious level," said Castro, adding that doctors from the nation's armed police have kept Troncoso in a cell without cardiovascular or resuscitation equipment, despite reports they have received from the health monitors.

The monitoring group has called for Troncoso to be transferred to Chilean capital Santiago, saying that she is isolated and is pressed by the police.

"The hunger striker cannot be placed in the hands of a state doctor, but must be placed in the hands of a trusted medical team," said Castro. The right to protest until demands are met should be respected, she added.

Troncoso has been jailed in accordance with the nation's Anti-Terrorist Law, brought in by Chile's 1973-1990 military dictatorship. Human rights groups in the nation have strongly criticized the use of the law.