A section of the mosque was destroyed in the blast.

According to reports, the target of the blast was the policemen.

The outlawed Tehreek-e-Taliban Pakistan (TTP) had taken responsibility for the attack, reports Geo News.

147 others were injured in the blast.

According to security officials, the suicide attacker was present in the front row during the Zuhr prayer when he exploded himself, injuring dozens of faithful, the Pakistani news channel reported.

Several footage of the blast site has now gone viral on the internet.

Sahibzada Noor Ul Amin, Imam of the mosque, was also killed in the blast, police told Geo News.

Prime Minister Shehbaz Sharif has left for Peshawar where he will be briefed on all aspects about the blast, the PM Office said in a statement as quoted by the news channel.

Capital City Police Officer, Peshawar (CCPO) Ejaz Khan, while talking to media, told Geo News that it was too early to say anything as many policemen are still trapped under the rubble.

"We are currently focused on the rescue operation. We cannot say with surety but there is a smell of explosives inside the mosque," said the CCPO.

"Close to 300-400 policemen usually offer prayers at the Zuhr time. If a blast has taken place inside police lines then it is a security lapse but an investigation into the matter can reveal further," said the CCPO.

Former Pakistan PM Imran Khan tweeted: " Strongly condemn the terrorist suicide attack in police lines mosque Peshawar during prayers. My prayers & condolences go to victims families. It is imperative we improve our intelligence gathering & properly equip our police forces to combat the growing threat of terrorism."