According to the TV, the blast took place at about 02:00 p.m. local time when a teenager suicide bomber aged about 16 blew himself up in a mosque at the Ghondi area of Jamrud, a district in Pakistan's northwest tribal area of Khyber Agency which borders Afghanistan.

Hundreds of people were offering Friday prayers inside the mosque when the attack took place, said local media reports.

Some reports said that over 100 people were inside the mosque hit by the blast while others put the number at 400 to 700.

Local TV footage showed that the mosque partially collapsed following the huge blast and many people were feared buried under the debris of the collapsed building.

An estimated 40 people injured in the blast were rushed to nearby hospitals while some 50 critically injured people have been shifted to the Lady Reading Hospital and other hospitals in Peshawar, a city which is about 50 kilometers away from the blast site.

Xinhua