A worshipper at the Imambargah mosque in Islamabad where dozens of people were killed in a suicide blast on Friday described an "extremely powerful" explosion ripping through the building just after prayers started.
Muhammad Kazim, 52, told AFP he arrived at the Imambargah Qasr-e-Khadijatul Kubra mosque shortly after 1:00 pm (0800 GMT) on Friday and took up a place around seven or eight rows from the Imam.
"During the first bow of the Namaz (prayer ritual), we heard gunfire," he told AFP outside the Pakistan Institute of Medical Sciences (PIMS) hospital, where many of the wounded were brought for treatment.
"And while we were still in the bowing position, an explosion occurred," he said.
Kazim, who is from Gilgit-Baltistan and lives in Islamabad, escaped unharmed, but accompanied his wounded friend to the PIMS hospital for treatment.
"It was unclear whether it was a suicide bombing, but the explosion was extremely powerful and caused numerous casualties," Kazim said.
"Debris fell from the roof, and windows were shattered," he added. "When I got outside, many bodies were scattered... Many people lost their lives."
The Islamic State group has claimed responsibility for the attack, according to the SITE Intelligence Group, which monitors jihadist communications.
Another worshipper, Imran Mahmood, described a gunfight between the suicide bomber, a possible accomplice and volunteer security personnel at the mosque.
"The suicide attacker was trying to move forward, but one of our injured volunteers fired at him from behind, hitting him in the thigh," Mahmood, in his fifties, told AFP.
"He fell but got up again. Another man accompanying him opened fire on our volunteers," he said, adding the attacker "then jumped onto the gate and detonated the explosives".
As of Saturday morning, the death toll stood at 32, with at least 169 wounded.
The attack was the deadliest in the federal capital since September 2008, when 60 people were killed in a suicide truck bomb blast that destroyed part of the five-star Marriott Hotel.
- Lax security -
Describing the aftermath of the attack, Kazim said unhurt worshippers went to the aid of those wounded.
"People tried to help on their own, carrying two or three bodies in the trunks of their vehicles, while ambulances arrived about 20 to 25 minutes later," he told AFP.
"No one was allowed near the mosque afterwards."
Kazim, who has performed Friday prayers at the mosque "for the past three to four weeks", said security had been lax.
"I have never seen proper security in place," he told AFP.
"Volunteers manage security on their own, but they lack the necessary equipment to do it effectively," he said.
"Shiite mosques are always under threat, and the government should take this seriously and provide adequate security," he added.
IS claims responsibility
IS said one of its militants had targeted the congregation, detonating an explosive vest and "inflicting a large number of deaths and injuries", according to the SITE Intelligence Group, which monitors jihadist communications.
- Bodies, bloodied clothing, debris -
AFP journalists at the Pakistan Institute of Medical Sciences hospital saw several people, including children, being carried in on stretchers or by their arms and legs.
Medics and bystanders helped unload victims with blood-soaked clothes from the back of ambulances and vehicles. At least one casualty arrived in the boot of a car.
Friends and relatives of the wounded wept and screamed as victims -- dead or alive -- arrived at the hospital's heavily guarded emergency ward.
Another team of AFP journalists saw armed security forces outside the mosque, where pools of blood were visible on the ground.
Yellow crime-scene tape surrounded an investigation area, with shoes, clothing and broken glass scattered around the site.
Videos shared on social media, which AFP was not able to verify immediately, showed several bodies lying near the mosque's front gate, with people and debris also strewn across the red-carpeted prayer hall.