- Pakistan security forces have cordoned off the area
- Helicopters are evacuating the wounded
At least 20 people were killed and more than 40 were wounded, according to the media wing of Pakistan's military.
The improvised explosive device blast occurred in a vegetable market, where a large number of people were gathered, according to Ikramullah Khan, a senior government official in Parachinar.
Security forces have cordoned off the area, and a search operation is currently underway, Khan said. He added that Pakistan Army helicopters are evacuating the injured.
A spokesman for the Pakistan Taliban -- also known as the Tehreek-e-Taliban Pakistan (TTP) -- says the group was targeting Shiites in this attack. The explosion was revenge for the killings of Malik Ishaq and Asif Chotu, according to Mohammad Khurrassani, the spokesman.
Ishaq and Chotou were leaders of banned group Lashkar-e-Jhangvi, and both were killed in separate encounters by police officials.
Chotu was killed by police earlier this week near Sheikhupura, about 40 kilometers northwest of Lahore. He had a bounty of $50,000 on his head by various Pakistani authorities. Ishaq was killed in 2015
during a shootout after armed men on motorcycles ambushed a police convoy that was transporting him between prisons in Punjab province.
Lashkar-e-Jhangvi is known for targeting Shiites in Sunni-majority Pakistan, including a series of bombings in early 2013 that left more than 160 people dead in Balochistan,
the volatile province in southwest Pakistan that borders Afghanistan and Iran.
The Kurram region has endured many militant attacks because it is on the border with war-torn Afghanistan.