Pakistanis observe the site of a bomb blast outside a Shiite mosque in Hangu. (AFP/Getty Images )
PESHAWAR, Pakistan -- A powerful suicide bomb blast killed at least 23 people Friday outside a Shiite Muslim mosque in a part of Pakistan's troubled northwest plagued by sectarian violence.
The bomber detonated his explosives as worshipers attending prayers at a mosque in the town of Hangu were leaving the building, local officials and witnesses said. The blast also injured more than 35 people, some of whom were transported to hospitals in critical condition, said Sahibzada Muhammad Anees, a Hangu administration official.
Hangu is just east of Pakistan's volatile tribal areas that serve as sanctuaries for an array of Islamist militant groups, including the Pakistani Taliban and Al Qaeda. The Hangu region is populated by Sunni and Shiite Muslims, who have clashed numerous times in the past.
Many of the dead and wounded were Shiites, but some were also Sunnis either at a nearby Sunni mosque or gathered at the area's marketplace, where Sunni run small shops. No group immediately claimed responsibility for the attack.
For years, the Shiite Muslim community in Pakistan has been targeted by Sunni militant groups that regard Shiites as heretics. According to the New York-based Human Rights Watch, more than 400 Shiite Muslims were killed in sectarian attacks in 2012 in Pakistan.
Earlier this month, twin bomb blasts killed 86 people, most of them Shiites, at a billiards hall in a Shiite neighborhood in the southwestern city of Quetta.
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Ali is a special correspondent based in Peshawar. Staff writer Alex Rodriguez in Islamabad contributed to this report.