A bomb exploded in the crowded bazaar of Parachinar city, located on Pakistan's northwestern tribal region on Sunday, killing at least 12 people and wounding more than dozens, officials say.

The death count is expected increase in the aftermath of the explosion, which occurred at the Eidgah used-clothes market in Parachinar city, which is the capital of the Kurram tribal district on the border with Afghanistan.

Two senior police officials have confirmed the incident, saying, "A bomb disposal squad has reached the spot and is trying to ascertain the nature of the the blast."

Local Television feeds showed hundreds of males fleeing the vicinity as police tried to cordon off the location while ambulances rushed to the site, according to NDTV.

A doctor at the local district headquarters hospital had said that most of the people who entered were in a critical condition. Most of the wounded were rushed the hospital once the explosion had occurred. No one took responsibility for the attack, but such occurrences are not an uncommon sight, as there have been numerous clashes between the Sunnis and the Shiites, who compose 20 percent of the population of Pakistan, which is over 200 million, The Hindustan Times reported.

Media reports suggest that the explosion was carried out through a planted device, and two suspects have been taken into custody from the blast site. The Kurram agency is adjacent to North Waziristan, where operation Zarb-i-Azb is in progress against the Tehrik-i-Taliban and other insurgent groups. Kurram is a small town consisting of a total population of about 40,000 people of different tribes, races and faiths.

Kurram was also one of the key routes for militant movement across the border. It has witnessed several kidnappings and sectarian attacks in the past few years, according to The Times of India.