A suicide bomber killed at least 50 people when he blew himself up in a crowded mosque near a security check post in Jamrud Town of Khyber Agency on Friday.
The two-storey shrine also collapsed in the blast.
In one of the worst terror strikes in the country, the mosque situated in Jamrud area of Khyber tribal agency was targeted leaving at least 100 persons injured. About 300 persons were reported to be inside the mosque at the time of the attack.
Assistant political agent Fida Bangash of Khyber Agency told TV channels that at least 50 people were killed after a suicide bomber blew himself up. Among the dead were 15 members of the local political administration and the Khasadar force.
Officials said the toll could rise since some victims were believed to be buried in the rubble.
About 30 personnel from the local Khasadar militia were in the mosque, which caved in after the blast, and officials said they could have been the target of the attack.
Tariq Hayat, the political agent of Khyber Agency, said the attack was carried out by a suicide bomber. Other officials said the attacker had rammed an explosive-laden vehicle into the mosque, which is located near a Khasadar check post on the Pakistan-Afghanistan highway.
No group claimed responsibility for the strike.