JALALABAD, Afghanistan - Dozens of worshippers have been killed and scores more wounded Friday in an explosion at a mosque in Nangarhar province, in eastern Afghanistan.

Attaullah Khogyani, Nangarhar provincial spokesman said sixty-two people were killed in the attack, while Reuters Thomson said another 100 people were wounded in the blast in Haska Mina district, also known as the Deh Bala district, near the border with Pakistan. Many of the casualties are believed to have been members of the Afghan National Army. By Sunday the death toll had risen to seventy-two, with another 3 people still missing,

The blast, which is said to have caused the mosque's roof to cave in, took place during Friday prayers in Haska Mina district, around 50 kilometres (30 miles) from the provincial capital Jalalabad.

The Taliban is operating in the region and so if ISIS, but at the point of writing no group had claimed responsibility for the attack.

"Dozens of people were killed and wounded and were taken in several ambulances," Haji Amanat Khan, a 65-year-old local resident, was quoted as saying by AFP.

While Friday's attack, believed to have been triggered by a suicide bomber, targeted the Afghan military, they were off duty and praying at a mosque which would render them as civilians.

"Civilian casualties are totally unacceptable," the UN's special representative in Afghanistan, Tadamichi Yamamoto, said.

In a statement released on Friday, UN Secretary-General Antonio Guterres declared those responsible for the attack must be held accountable. He extended his deepest sympathy and condolences to the families of the victims, and wished a speedy recovery to those injured.

The Secretary-General reiterated the solidarity of the United Nations with the people and government of Afghanistan.

The UN on Thursday reported that 1,174 civilians were killed and 3,139 injured from 1 July until 30 September, a 42% increase on the same time period last year.

(File photo: Afghan National Army cadets practice drills on the parade grounds at the Afghan National Defense University in Kabul, Afghanistan. Credit: Staff Sgt. Dustin Payne/U.S. Air Force).