Peshawar, Pakistan – Two extremists detonated bombs at a mosque in north-western Pakistan on Friday, killing around 50 people and injuring several others, police and rescuers said. The two bombers also died in the incident.

The men fought their way inside the mosque compound in the city of Peshawar by killing police guards before blowing themselves up in the packed main hall, police official Haroon Raheed said.

"We have retrieved around 50 bodies and more than 80 injured people from the rubble," said rescue service official Bilal Faizi.

The death toll may rise as more than a dozen of those injured are in critical condition, said Mohamed Asim, spokesperson for the city’s biggest Lady Reading Hospital, where most victims were brought.

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Rescuers, police, and volunteers have completed the search, Faizi said.

The mosque is located in a densely-populated Shiite neighborhood in the center of city and most victims were Shiite Muslims, local resident Siraj Uddin said.

An eyewitness who was inside the hall told Pakistan’s Dunya television he saw two young men running into the compound, firing shots randomly before the explosion.

"They shouted 'Allahu Akbar' and a huge explosion occurred. There was smoke and screams all over."

"I then saw several bodies lying on top of each other and a river of blood flowing on the floor."

No group has claimed responsibility for the attack so far, but both the Pakistani Taliban and the terrorist militia Islamic State have been targeting worshippers at mosques in Pakistan.

Violence has surged in the country since neighboring Afghanistan fell to the Taliban last year.

The Pakistani Taliban, a separate group from their Afghan counterparts, have stepped up their attacks against the country's security forces and civilians since the fall of Kabul.

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Pakistani officials have said the group is operating from the border regions of Afghanistan, where they have been based since they were driven out from their hideouts in Pakistan in a series of military offensives.

Around 80,000 Pakistanis have been killed in violence orchestrated by Islamist militant groups like al-Qaeda, the Taliban, and Islamic State.

The Islamic State terrorist group has claimed responsibility for the suicide attack on a mosque in north-western Pakistan in a statement late on Friday.

Updated figures show the attack killed 60 people and injured at least 200 more in the deadliest attack in the country in years, police and rescuers relayed. At least 50 of those injured are in critical condition, said Mohamed Asim, spokesperson for the city’s biggest medical facility, the Lady Reading Hospital, which is treating most of the victims.

The agency quoting sources said the Islamic State suicide bomber, identified as Julaybib al-Kabli, detonated a highly explosive belt. It is unclear if he acted alone or in a pair, as previously reported.

Of the members of the Pakistani police who were shot while guarding the site, one has been confirmed as killed, while the other has been reported as wounded.