With its Mughalesque features, gleaming white dome and minaret-like towers, the All Saints' church in Peshawar has been a symbol of interfaith harmony ever since it was built in 1883.

As in a mosque, worshippers remove their shoes before entering the historic building, where biblical quotations are emblazoned on the walls in English, Hebrew and Persian scripts.

Some of the congregation were in bare feet as they filed out of the Anglican church on Sunday morning straight into the blast zone of one of two suicide bombers from a Taliban faction that has vowed to kill non-Muslims until the US cancels its lethal drone strikes in the country.

A day later and a blood-soaked jumble of shoes still lies in a pile on the right-hand side of the tall wooden doors where female worshippers usually congregate.

According to a tally based on information from local officials, 85 people were killed and more than 100 injured, although one doctor who arrived at the scene moments after the blast believes that even more died but their bodies were recovered by relatives before they could be accounted for.

Whatever the number, it was Pakistan's worst attack on Christians, sparking impassioned, country-wide protests.

Christians are a tiny and politically weak minority in Muslim-majority Pakistan who suffer from prejudice and sporadic bouts of mob violence. But Sunday was the first time that bombs had been used to such deadly effect on worshippers.

It bore the hallmarks of similar attacks by sectarian terror groups whose attacks have caused huge casualties among Shia communities. And Sunday's atrocity was claimed by the Jundullah branch of the Tehreek-e-Taliban Pakistan (TTP), a group that has orchestrated attacks against Shias. On Monday, the TTP's main spokesman denied any involvement.

In the streets and lanes of Peshawar's old city, where All Saints' is located a short distance from one of the historic gates of the city walls, all of the tightly-knit Christian community knows or is related to one of the dead.

"He had made a promise to God that when he got better he would go to church," said Joel Fakhar, the 20-year-old son of a man called Khalid who returned to the church after months of serious illness had kept him away.

Their 52-year-old father had been looking forward to it, particularly the period after the service when the congregation spills out into the enclosed courtyard to chat.

"He was looking forward to seeing his friends," said Joel.

On Monday the bodies had all been removed from the area where hundreds of worshippers milled around in the moments before the blasts, but dark, blood-soaked patches remained. The walls of the church and surrounding buildings were pockmarked by shrapnel, the windows blown in.

"It's not safe for Christians in this country," said Mano Rumalshah, the bishop emeritus of Peshawar, who was standing in the courtyard, comforting sobbing parishioners who clasped his white robes.

"Everyone is ignoring the growing danger to Christians in Muslim-majority countries. The European countries don't give a damn about us."

Others echoed the bishop's warning, saying that Christians would only be safe if they left Pakistan. But others vowed to remain and show they were not afraid.

Many analysts predict that the attack will torpedo efforts by the government to negotiate with the TTP and other militant groups – a policy agreed at a meeting of all the leading parties earlier this month.

On Sunday the prime minister, Nawaz Sharif, said during a visit to London that the government would be "unable to proceed further" with talks following the Peshawar attack.

Some diplomats think the government's offer of seemingly impossible negotiations with a loose coalition of violent Islamists intent on toppling the state was a strategy designed to demonstrate the futility of talks and build public support for a military crackdown on terrorist sanctuaries.

Nonetheless the policy has been angrily criticised, with many arguing it is tantamount to appeasement.

"How can you talk to people who are killing civilians?" said Tahir Naveed Chaudhary, chairman of the Pakistan Minorities Alliance. "We are just wasting time and we will lose more people. This is a message that the government must take concrete steps against terrorists."

He had harsh words for Imran Khan, the opposition leader whose party controls the provincial government of Khyber Pakhtunkhwa, the north-western province that is home to much of the country's militant violence.

Khan has strongly promoted his solution to militancy, which includes ending Pakistan's support for the Nato mission in Afghanistan, withdrawing troops from the autonomous tribal areas and striking a deal with the Pakistani Taliban.

On Sunday he suggested the church attack was a deliberate effort by unnamed forces to scupper talks. He also linked militant violence to US drone strikes, prompting his many critics to accuse him of making excuses for terrorism.

"By going soft on these people he is showing that he is pro-Taliban," said Chaudhary.

But, in a sign of how hard it will be to persuade a sceptical public that tough action is required against militant groups, some victims of Sunday's bombing said they agreed with Khan.

"It's because of the drones and the US war on terror," said Amir Masih, a 25-year-old lying in a cacophonous ward in the city's Lady Reading hospital packed with survivors recovering from severe injuries, emergency surgeries and the grief of losing friends and relatives.

In addition to his badly injured wife in the adjacent bed, Masih's two sons and daughter were killed.

"We have no choice," he said. "We have to negotiate with them."