LIMA (Reuters) - Peruvians marched through the streets on Friday to urge President Pedro Pablo Kuczynski not to pardon the country’s former leader Alberto Fujimori, who is serving a 25-year prison sentence for human rights violations.

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Kuczynski’s promise not to pardon Fujimori during last year’s presidential election helped him scrape together a narrow victory against Fujimori’s daughter, Keiko Fujimori.

But last month Kuczynski proposed a potential pardon for Fujimori, 78, for health reasons as his finance minister was ousted by Congress, which is dominated by Fujimori’s supporters.

“It would be a betrayal. A betrayal of his word and his promise to the families of the victims of the dictatorship,” said protest organizer Jorge Rodriguez.

At least 2,000 protesters participated in the march through the streets of Lima, witnesses said.

“Fujimori’s human rights violations cannot be pardoned for humanitarian reasons,” said Giancarlo Portugal, a 26-year-old student who participated in the march.

Fujimori has been convicted of leading groups that massacred civilians and kidnapped journalists during his years in office from 1990-2000. Despite his autocratic style, Fujimori still has a solid following among Peruvians who credit him with fixing an economy in crisis and quashing a bloody leftist insurgency.

A May Ipsos poll found that 59 percent of Peruvians back a humanitarian pardon for Fujimori.

In an interview with local broadcaster RPP on Friday, Kuczynski said his decision would be based strictly on a medical review that should be completed by the end of year.

“I’ll follow the medical recommendation,” Kuczynski said.

But the proposed evaluation, which was not requested by Fujimori, is widely seen as a political gesture.

While pardoning Fujimori might help Kuczynski ease tensions with Congress, it would anger the leftist groups that helped elect him.

Kuczynski, who took office nearly a year ago to cap a distinguished career in finance and public administration, has vowed to transform Peru into a modern country and is leading regional efforts to pressure Venezuela to enact democratic reforms.

Fujimori’s doctor, Alejandro Aguinaga, said Friday that Kuczynski’s committee for presidential pardons has not received any new information about Fujimori’s health.

But Aguinaga said Fujimori suffers from various ailments that merit a pardon, including a recurrent growth on his tongue, a hernia in his back and a recent episode of an abnormally fast heart beat.