GENEVA- The U.N. human rights office appealed to Pakistan on Friday to refrain from resuming executions after the massacre of 141 people in a Peshawar school, saying this would not stop terrorism and might even feed a "cycle of revenge".

Prime Minister Nawaz Sharif lifted Pakistan's moratorium on capital punishment on Wednesday, a day after Taliban gunmen attacked the school and killed 132 students and nine teachers. The slaughter has put pressure on his government to do more to tackle the Islamist Taliban insurgency.

The U.N. rights office also urged Pakistan's army and security forces to respect international law during their counter-terrorism operations so as to avoid exacerbating bloodshed.

"To its great credit, Pakistan has maintained a de facto moratorium on the death penalty since 2008, and we urge the government not to succumb to widespread calls for revenge, not least because those at most risk of execution in the coming days are people convicted of different crimes, and can have had nothing to do with Wednesday's premeditated slaughter," U.N. human rights spokesman Rupert Colville said.

There is no evidence that imposing the death penalty has any impact whatsoever in deterring terrorism or other serious crimes, he said in remarks sent to journalists in Geneva.

"In fact, by feeding a cycle of revenge, it may even be counter-productive," Colville said.

He voiced hope that the perpetrators or planners of the mass school killing be brought to justice as soon as possible, while urging restraint by the Pakistani security forces.

"It is extremely important to maintain the moral and legal high ground, as human rights violations by authorities, especially civilian casualties, simply harden attitudes and feed the spiral of violence," Colville said.

The Pakistani Taliban, waging war to overthrow the government and establish an Islamic state, had pledged to step up attacks in response to a major, ongoing army campaign against the insurgents in tribal areas.