Peshawar attack
People carry the coffin of a male student who was killed in Tuesday's attack on the Army Public School, which was attacked by Taliban gunmen, during his funeral in Peshawar,Reuters

A day after Pakistan saw the most gruesome attack on a school in Peshawar, the country's Prime Minister Nawaz Sharif has lifted a ban on death penalty in terrorism cases.

This comes as three days of official mourning is underway in the country after 141 people, 132 of them children, were killed as heavily armed militants went on a shooting rampage running from classroom to classroom inside a military school in the northwestern city.

"It was decided that this moratorium should be lifted. The prime minister approved," government spokesman Mohiuddin Wani said on Wednesday, referring to the ban on death penalty for terrorism charges.

The move was proposed by a ministerial committee right after the attack took place on Tuesday and was approved by PM Sharif, the official added.

The attack was carried out by six militants at around 10 am local time after they bypassed the heavily guarded main entrance and slipped in through a back entrance that was less frequently used, witnesses said.

The fanatics rushed from room to room, shooting randomly at any human they saw in front of them, children or otherwise, registering their name in history as the perpetrators of the biggest ever terrorist attack that Pakistan saw.

At least 500 pupils aged between 10 and 20 years were inside the building when the attack started. When the gunfight between the Taliban and Pakistani forces intensified, at least three of the militants blew themselves up, instantly producing several charred bodies.

The killing of the innocent children sparked controversy even within the Taliban outfit. The organisation's Afghan branch has distanced itself from the act, claiming such acts were against Islam.