LIMA (Reuters) - Thousands of Peruvians marched on Thursday to protest the president’s recent pardoning of former authoritarian leader Alberto Fujimori, calling for new general elections as a graft scandal ensnares established politicians.

The demonstrations capped a head-spinning week in which President Pedro Pablo Kuczysnki warned about a new rise of Fujimori’s authoritarian movement, only to pardon him three days later after Fujimori’s loyalists in Congress saved him from an impeachment bid.

Waving Peruvian flags and chanting “down with the corrupt,” protesters called the pardon payback for keeping Kuczynski in power.

“I’m marching against this outrage, this insult that we feel now that the dictator Fujimori has been pardoned,” said Milagros Reboyo, a 26-year-old university student at a march in Lima.

The Christmas Eve pardon cleared Fujimori’s convictions for graft and human rights abuses 12 years into a 25-year prison sentence, and shields him from a pending trial for a 1992 death squad massacre.

Fujimori’s 2009 sentencing had earned Peru international plaudits in efforts to fight impunity. United Nations human rights experts called the pardon an appalling “slap in the face” for his victims and a major setback for the rule of law.

Fujimori, who remained in a hospital with blood pressure and heart problems on Thursday, governed Peru with an iron fist from 1990-2000 after being swept to power by a populist wave in 1990 elections. While many consider him a corrupt and ruthless dictator, others credit Fujimori with pulling Peru from economic ruin and quashing a leftist insurgency.

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On Thursday, Kuczynski said the pardon was fundamentally about forgiveness.

“The country can’t remain divided by political struggles that only hold the country back from continuing to make progress,” Kuczynski’s office said in a statement.

In Lima, the march was largely peaceful. But police fired tear gas at protesters who veered from the permitted route to march in front of Kuczynski’s house in the financial district.

Four people were arrested, the interior ministry said. It declined to estimate the size of the protests, saying “we don’t want to get into that debate.”

One of the groups that helped organize the protests said 60,000 took part in Lima.

Protests were also held in other Peruvian cities and foreign capitals.

The pardon has deepened the disgust that many Peruvians feel toward mainstream politics, after a graft scandal involving Brazilian builder Odebrecht has ensnared two former presidents in the past year.

Kuczynski and opposition leader Keiko Fujimori, Fujimori’s daughter, are also under investigation for their ties to Odebrecht. On Thursday, the two separately underwent questioning by prosecutors investigating Odebrecht’s partners in crime.

Both deny any wrongdoing and have promised to cooperate with investigations.