Peru's former President Alberto Fujimori asks for forgiveness from Peruvians as he lies in hospital bed in Lima, Peru, in this still image taken from a video posted on Facebook on December 26, 2017. Fujimori Handout/Reuters TV via REUTERS

GENEVA (Reuters) - Peruvian President Pedro Pablo Kuczynski’s pardon of his predecessor Alberto Fujimori is an appalling “slap in the face” for his victims and a major setback for the rule of law, a group of U.N. human rights experts said on Thursday.

“A humanitarian pardon has been granted to someone convicted of serious crimes after a fair trial, whose guilt is not in question and who does not meet the legal requirements for a pardon,” they said in a statement.

Kuczynski pardoned the ailing Fujimori three days after Fujimori loyalists in the opposition-ruled Congress saved Kuczynski from being ousted in a corruption scandal.

“We are appalled by this decision. It is a slap in the face for the victims and witnesses whose tireless commitment brought him to justice,” said the statement, issued jointly by the U.N. working group on enforced disappearances and by U.N. special rapporteurs Agnès Callamard and Pablo de Greiff.

They are independent experts mandated by the U.N. Human Rights Council to investigate extrajudicial executions and the promotion of justice respectively.

Fujimori had served 12 years of a 25-year sentence for corruption and human rights crimes in his 1990-2000 right-wing government. Kuczynski’s decision cleared him of convictions and shields him from being tried in pending judicial processes.

The U.N. experts said his conviction for crimes including extrajudicial killings, enforced disappearances and kidnapping had been hailed as a major achievement in the fight against impunity, and international law restricted the granting of pardons in such serious cases.

They said his pardon was politically motivated and undermined the work of the Peruvian judiciary and the international community to achieve justice, adding: “It is also a major setback for the rule of law in Peru.”

Kuczynski’s government has repeatedly denied that a pardon for Fujimori was part of political negotiations.