At least 100 people, most of them policemen, were killed and more than 225 people wounded in the suicide blast on Monday, the deadliest in a decade as attacks by armed groups are on the rise.
“I was standing with my friends when the blast threw us away, and just as we tried to get our bearings, within a few seconds, the entire roof collapsed,” Rehman, who works in the telecommunications department for the police, told Al Jazeera.
“We were lucky enough to find a way and crawled out, but my leg was badly wounded,” Rehman said. Like most of the wounded, he was brought to the city’s main hospital, Lady Reading.
Rehman said he is determined to carry on.
“Even though I lost a few of my friends, it will not deter me,” he said as he lay with seven other patients in a hospital ward. “I will go back to my job. This is my duty. I will not be afraid of this attack.”
Prime Minister Shehbaz Sharif has condemned the attack and promised “stern action”. Officials have announced an investigation into the blast in a high-security police zone.
“The sheer scale of the human tragedy is unimaginable,” Sharif tweeted after visiting Peshawar. “This is no less than an attack on Pakistan.”
A faction of Tehreek-e-Taliban Pakistan (TTP), also known as the Pakistani Taliban, claimed responsibility for the attack, but a TTP spokesman later denied a role in the blast.
A tenuous months-long ceasefire between the TTP and Pakistan collapsed last year and the group has since intensified its attacks against Pakistani security personnel.
Yashwa Tariq, a 28-year-old police constable, was on a duty in Peshawar when he received a call from a friend on Monday afternoon telling him that his house next to the mosque had been damaged in an explosion.
“My heart just sank,” said Tariq, who rushed home. He described what he found as rubble and utter chaos.
“All my neighbours and friends were trying to remove the debris with their bare hands,” he said. “I managed to find my son who was hurt, completely covered in dust and couldn’t open his eyes.”
Tariq’s wife, sister and grandmother were trapped under the collapsed roof in another room. The police constable managed to get his son out and rushed him to Lady Reading Hospital, praying that the rest of his family would survive.
His wife, son and sister did, but his maternal grandmother, Rasheeda Bibi, was killed.
“My wife has suffered a fracture in both her legs,” Tariq told Al Jazeera. “My sister has a gash in her head. My son is suffering from trauma. My grandmother has died. I have nowhere to go back to. I don’t have a home anymore.”
Several other houses next to the mosque where policemen live were also damaged.
The impact of the blast was so severe that it brought down the roof over the main prayer hall of the mosque, under which close to 300 worshippers were about to begin their prayers.
Kashif Aftab Abbasi, a senior superintendent of police operations in Peshawar, confirmed to Al Jazeera that initial police investigations found that the blast was caused by a suicide bomber and the vast majority of deaths was caused by the roof collapse.
More than 90 percent of those who died worked for the police.
The explosion in the Police Lines Mosque was the first major attack in Peshawar since March when a Shia mosque was attacked by the Islamic State of Khorasan Province, killing more than 60 people.
Muhammed Asim, a Lady Reading Hospital spokesman, said the situation at the facility on Monday was “overwhelming” as ambulances brought in droves of dead and wounded.
Unlike Rehman, Yasir Khan – a police constable who also lives in Police Lines, a secured part of Peshawar where important government installations are – says the incident has shaken his confidence.
“We are aware of the attacks on police and security officials,” the 29-year-old told Al Jazeera while standing near the rubble of the mosque. “We expect attacks on checkpoints. But we could never have imagined an attack taking place inside our compound. It is so heavily guarded.”
Deciding to leave his job has never once occurred to him, he said. “This is the job that feeds us. My father was in the police as well. What else am I going to do if not this? My wife asked me to quit the job and move back to our village, but I told her duty comes first.”
Kamran Khan, a government teacher, said that when he saw the news of the explosion on TV, he rushed to the blast site in the Police Lines compound. His brother Irfanullah as well as his cousin Shafiq worked in the police department.
His brother was among those killed while his cousin was admitted to Lady Reading Hospital.
“We are eight siblings, and Irfanullah was third.” Khan said. “He worked as a government teacher like me for the longest time, but he always aspired to wear a uniform.”
Irfanullah, who joined the police in 2010, is survived by five children, two sons and three daughters.
“I used to try to stop him from joining the force,” Khan said. “But now, I will not only encourage his son to follow in his father’s footsteps, I will also push my own son to join. I want them to serve the nation and honour Irfanullah’s name.”
Abid Hussain is Al Jazeera’s digital correspondent in Pakistan. He tweets @abidhussayn.