Afghanistan: A bomb exploded at a mosque in Nangarhar province during a prayer ceremony today, leaving at least 62 dead and dozens injured.

The blast collapsed the mosque's roof in Haska Mina district, Nangarhar province, eastern Afghanistan as followers were praying, spokesman of the governor Attaullah Khogyani said. No organization has claimed responsibility for the attack.

"Dozens of people were killed and the injured were taken to emergency," said Haji Amanat Khan, a 65-year-old local resident.

A Taliban spokesman called the attack a "major crime", insisting the group was irrelevant and blamed the alleged Islamic State rebel (IS) or government forces.

The attack comes a day after the United Nations warned that violence in Afghanistan had reached an "unacceptable" level, emphasizing that "Afghanistan has faced extreme levels of violence for years" although The parties have promised to "prevent and minimize damage to civilians".

"Civilian casualties are completely unacceptable," Tadamichi Yamamoto, the UN's special representative in Afghanistan, said, stressing the importance of negotiations that led to a ceasefire and long-term political deal.

Location of Nangarhar province, Afghanistan. Graphics: BBC.

According to data from July 1 to September 30, 1,174 people in Afghanistan were killed and 3,139 injured, an increase of 42% over the same period last year. The UN blames the surge in casualties on "anti-government elements" such as the Taliban, which have been waging a bloody insurgency in Afghanistan for more than 18 years.