Former Peruvian President Alberto Fujimori remained in a Lima hospital on Monday, a day after he was granted a medical pardon for his 25-year sentence for crimes against humanity.
Protesters clashed with police who lobbed tear gas to break up the crowds gathered in several plazas across the Peruvian capital.
Many Peruvians are angry that Fujimori, 79 and ailing, was pardoned by President Pedro Pablo Kuczynski, despite the gravity of his crimes, Fujimori was found guilty of human rights abuses, corruption and the sanctioning of death squads.
Fujimori served as president of Peru from 1990 to 2000.
He was admired by some Peruvians for combating Maoist rebels, whereas his critics consider him a corrupt dictator.
His supporters gathered in solidarity outside the Lima hospital where Fujimori is being treated.
Kuczynski released a statement Sunday that said a medical board had evaluated Fujimori and determined that "he suffers from a progressive, degenerative and incurable disease and that prison conditions mean a serious risk to his life, health and well-being."