At least 100 people have died in relation to a suicide bombing at a mosque in Pakistan.

Mohammad Asim, a spokesperson for the Lady Reading Hospital, confirmed the rising death toll on Tuesday (January 31) via NBC News, one day after the incident took place. Riaz Khan Mahsud, commissioner of the Peshawar division of Khyber Pakhtunkhwa province, had previously said that responders were still recovering bodies at the scene of the attack.

A bomber set off explosives at the mosque during an afternoon prayer, which caused the facility's roof to cave in. The mosque is located inside a walled compound that also houses the Peshawar Police headquarters and many of the victims were reported to be police officers.

Deputy commissioner Shafiullah Khan said 177 others were injured during the attack and 57 are currently hospitalized, including some reported to be in critical condition. About 300 worshippers were inside the mosque at the time of the bombing, according to Peshawar Police Chief Ijaz Khan.

“A portion of the building collapsed, and some of the people are alive but stranded there,” Khan said Monday via NBC News. “Our teams are engaged in cutting the steel to recover them.”

Authorities haven't yet determined how the bomber was able to evade security at the compound as the bomber was confirmed to have not been a member of the police force.

Sarbakaf Mogmand, a commander of the Pakistani Taliban, which has waged rebellion in Pakistan for the past 15 years, initially claimed responsibility for the bombing in a post shared on Twitter, however, spokesperson Mohammad Khursani later denied the group's involvement in the attack.

“As per our principles, carrying out attacks in mosques, seminaries and other holy places cannot be defended and the perpetrators are liable to be punished,” Khursani said in a statement obtained by NBC News, though not addressing Mogmand’s previous claim of responsibility.