PARACHINAR: At least 22 people were killed and 100 others wounded Friday when a car bomb tore through a busy marketinfo-icon in a Pakistani tribal belt dominated by Shiainfo-icon Muslims, officials said.

Eyewitnesses said that security personnel were busy checking devotees at the central Imambargah, inside the crowded market in Parachinar, capital of Kurram tribal district, ahead of Friday prayers, when the blast occurred.

An unidentified person parked an explosive laden car next to women's entrance of the Imambargah and soon a massive explosion shook the area. Frantic bystanders were seen rushing to help the wounded.The attack comes after a wave of militant violence killed 130 people across Pakistaninfo-icon in February, unnerving citizens who had been emboldened by improving security and prompting a military crackdown.

"We have 22 dead bodies here at the hospital and 57 injured, including women and children," Moeen Begum, a surgeon at the local government-run hospital, was quoted as saying. She said death toll could rise as the condition of many of the injured was grim. 

Prime Minister Nawaz Sharifinfo-icon condemned the blast, saying it was a "duty" to seek the "complete annihilation" of terrorism in Pakistan, and ordering assistance for local authorities.

But angry residents quickly accused security forces of failure, with small protests breaking out in Parachinar.

AFP quoting an eyewitness described seeing security forces fire on the protesters, injuring some.

"Terrorists crossing dozens of checkposts and carrying out attacks puts a question mark over the progress of security institutions," said Allama Raja Nasir Abbas, chief of a Wahdat-ul-Muslimeen party.

A parliamentarian from Parachinar, Sajid Hussain, said it was a suicide attack and was preceded by gunfire. "The attack took place in a busy area and a women's mosque appears to be the target," he said.

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 usinfo-icon in private cars and ambulances and we have received over three dozen patients so far," Hussain told Reuters.

Military's mediainfo-icon wing ISPR said that a chopper has been dispatched to the blast site to shift the injured to nearby hospitals.

A banned outfit Jamat-ul-Ahrar through a video message claimed responsibility for the attack.

The group was also part of the wave of attacks which shook the country in February, claiming responsibility for a suicide bomb in Lahore which killed 14 people.

February's assaults also included a suicide blast at a Sufi shrine in Sindh province which killed 90 people and was claimed by Islamic Stateinfo-icon.

Parachinar was the location of the first major militant attack in Pakistan in 2017, a bomb in a different market which killed 24 people in January and was also claimed by the Pakistani Taliban and Lashkar-i-Jhangvi al-Alami.

The armyinfo-icon had launched Operation Raddul Fasaad last month following a spate of terror attacks in the country, which claimed more than a hundred lives and left hundreds others injured. The operation seeks to eliminate the "residual/latent threat of terrorism", consolidating the gains made in other military operations, and further ensuring the security of Pakistan's borders.

Kurram is one of Pakistan's seven semi-autonomous tribal districts which are governed according to local laws and customs and the only part of Pakistan's border region that has a significant Shia population and thus frequent target of terror attacks.