An explosion apparently targeting a mosque in the Pakistani city of Parachinar, in the remote northwestern tribal region bordering Afghanistan, killed at least five people and wounded dozens, local officials said.
It is suspected to be a remote controlled device planted in a vehicle, Ikramullah Khan, a political agent for Kurram agency, told Al Jazeera, adding that at least five wounded were in critical condition.
Television footage from the scene showed damaged buildings in a busy marketplace, with crowds gathered around the site. Local officials said the blast took place near the entrance to a Shia mosque.
Mumtaz Hussain, a doctor at the local Agency Headquarters Hospital, said five bodies, including a woman and two children, and more than three dozen wounded had been brought to the hospital and an appeal had been issued for blood donors.
"Patients are being brought to us in private cars and ambulances and we have received over three dozen patients so far," Hussain told Reuters.
Sajid Hussain Turi, a member of parliament from Kurram, told local television channel Geo:
"There have been threats for at least two months, but I am sad to say the administration and the FC soldiers have just been bothering people here ... and yet this attack still happened! This is both a question mark [on the security arrangements] and to be marked with sadness."
Parachinar is the capital of the Kurram tribal area in Pakistan's northwest, located about 275km west of the capital Islamabad. The district has seen several blasts targeting its sizeable Shia Muslim minority.
In January, at least 25 people were killed and 87 wounded when a bomb went off in a busy vegetable market in Parachinar.
Last month, more than 70 people were killed and dozens wounded in an attack on a crowded Sufi shrine in southern Pakistan.
The attacks have shattered hopes that Pakistan may have come through the armed group's violence that had scarred its recent history and increased pressure on Prime Minister Nawaz Sharif's government to show it was improving security.