Mr. Fujimori, 79, would have remained in prison until age 93 if he had served his full sentence.
Suffering from arrhythmia, tongue cancer and other ailments, Mr. Fujimori had requested a humanitarian pardon. He was taken from his prison cell to a hospital on Friday after a drop in blood pressure, doctors said.
In a statement, Mr. Kuczynski’s office said that a medical board had determined “that Mr. Fujimori suffers from a progressive, degenerative and incurable disease and that the prison conditions mean a serious risk to his life, health and integrity.” The board’s conclusions were presented to a presidential pardon commission, which recommended that Mr. Fujimori and seven other inmates be pardoned “for humanitarian reasons.”
Ronald Gamarra, a human rights lawyer and anti-corruption prosecutor, dismissed that characterization. “This pardon is fake and under no circumstance should it be considered a humanitarian pardon,” Mr. Gamarra said. “It is a political pardon.”
A son of Japanese immigrants, Mr. Fujimori was an obscure agricultural engineer and political novice when he ran for the presidency in 1990. He stunned the nation by placing a close second in a crowded field and then defeating the establishment favorite, the novelist Mario Vargas Llosa, in a runoff.
But he also ran roughshod over Peru’s laws and institutions. He was lauded for suppressing two uprisings, the Shining Path and the Tupac Amaru Revolutionary Movement, but the brutality of his methods drew criticism worldwide and ultimately landed him in prison.
Mr. Fujimori, forced from power in 2000 after a television channel broadcast a videotape showing his intelligence chief, Vladimiro Montesinos, trying to bribe a congressman, fled to Japan, where he submitted his resignation by fax from a hotel in Tokyo. He was extradited to Peru from Chile in 2007 and later sentenced to 25 years in prison for atrocities that a military unit carried out early in his presidency, killing 25 people.
“There will be no peace, no democracy or justice when the pain of the family members who are victims of the atrocities of Fujimori and Montesinos is not respected,” Marisa Glave, a member of Congress from the leftist Nuevo Peru party, said Sunday.
Mr. Fujimori was believed to be the world’s first democratically elected former president to be found guilty of human rights violations in his own country. But even from prison he continued to command grass-roots support. His supporters took to the streets near the hospital where he was being treated to celebrate his pardon, wearing white T-shirts that read Freedom for Fujimori.
Marco Arana, a member of Congress from the leftist Broad Front party, condemned the pardon as a “slap in the face,” saying it would polarize Peru. “We reject this criminal act,” Mr. Arana said. “The president has made a mistake and it is an act of criminal politics.”