The explosion happened in the mosque located in the Police Line area of Peshawar during afternoon prayer, police said.

A suicide bomber blew himself up at the mosque as worshipers, including many policemen from nearby police offices, were performing afternoon prayer.

The assailant was able to gain access to the mosque in spite of security measures undertaken by the Pakistani police.

Peshawar Chief of Police, Muhammad Ijaz Khan, told local media that between 300 and 400 police officials were present in the area at the time.

The mosque was located inside a compound that includes the headquarters of the provincial police force and a counter-terrorism department. Twenty-seven of the deceased victims were police officers

Pakistani Prime Minister Shehbaz Sharif condemned the attack, stating that the attack is incompatible with Islam and that the entirety of Pakistan stands against the “menace of terrorism”.

“While the pain of the grieving families cannot be described in words, I express my heartfelt condolences & most sincere sympathies. My message to the perpetrators of today's despicable incident is that you can't underestimate the resolve of our people,” Sharif wrote on Twitter.

After the blast, the caretaker Chief Minister of Khyber Pakhtunkhwa Muhammad Azam Khan announced a day of mourning in the province. (ILKHA)