Thousands of Pakistanis Sunday mourned the 149 people -- mainly children -- massacred by the Taliban, as the government executed four more militants on death row despite an outcry by rights groups.
After the attack Prime Minister Nawaz Sharif ended a six-year moratorium on the death penalty, reinstating it for terrorism-related cases with the first executions of two militants taking place on Friday.
Four more were hanged in the eastern city of Faisalabad on Sunday.
Pakistan has described Tuesday's bloody rampage as its own "mini 9/11", calling it a game-changer in the fight against extremism.
Men, women and children from Peshawar and other cities visited the army-run institution to offer prayers for those killed in the country's deadliest-ever terror attack.
Flowers, bouquets, placards and lighted candles were placed in front of photos of murdered students.
Masons laid bricks and poured cement to raise the height of the wall around the Army Public School as mourners chanted slogans such as "Death to terrorists", "Long live Pakistan army", "The blood of martyrs will not go waste" and "Taliban are savages".
"What kind of a person can kill a child?" asked local resident Imdad Hussain.
"What kind of justice is this, what kind of Islam is this?" he asked, urging the government swiftly to wipe out terrorists.
A local woman, her face covered with a shawl, said parents had thought their sons and daughters would be safe in school. But now they believed their children were not safe anywhere.
"First they attacked mosques, then markets and now they have started attacking schools. We cannot tolerate this. We can die, but we will not let our children be killed," she said.
Shugufta Bibi, 28, told AFP her friend lost his son in Tuesday's attack and she had come to pay respects to his memory.
"I demand that the government close in on the terrorists and hang them in public," Bibi said.
The city's Christian community will cancel Christmas celebrations and will just hold a service on December 25, said the Rev Patrick John of All Saints Church.
- Six executions -
The two militants hanged Friday in the central province of Punjab were Aqil, convicted of an attack on army headquarters in Rawalpindi in 2009, and Arshad Mehmood -- sentenced for involvement in a 2003 assassination bid on former military ruler Pervez Musharraf.
Ghulam Sarwar, Zubair Ahmed, Akhlaq Ahmed and Rashid Tipu were hanged Sunday in the same prison for the attempted assassination.
Pakistan's decision to reinstate executions was slammed by human rights groups, with the United Nations also calling for it to reconsider.
Human Rights Watch on Saturday termed the executions "a craven politicised reaction to the Peshawar killings" and demanded that no further hangings be carried out.
Meanwhile, Interior Minister Chaudhry Nisar said some 300 suspects had been arrested from a suburb of Islamabad, and around 4,000 intelligence based raids made across Pakistan in the latest crackdown.
Nisar said a joint working group of parliamentary parties would complete its recommendation by Monday evening on the government's future course of action on eliminating terrorism.
The school massacre has been condemned even by the Afghan Taliban, who are loosely affiliated with the Taliban in Pakistan.
In a statement Sunday, the Al-Qaeda South Asia chapter also expressed grief at the killings and urged fellow militants to target only security forces.
Pakistan put all its airports on red alert Saturday as the military intensified operations in the lawless northwestern tribal areas.
The Taliban said the school attack by a suicide squad was revenge for the killing of militants' families in that offensive.
The military has since June been waging the assault against longstanding Taliban and other militant strongholds.
But a series of fresh strikes since the Peshawar attack, in which dozens of alleged militants were killed, suggest the campaign is being stepped up.