Pakistani officials say at least 56 people were killed and more than 30 wounded on January 30 in a bombing at a Shi'ite mosque in the southern province of Sindh.
The bombing occurred in the Lakhi Dar area of the town of Shikarpur, some 470 kilometers north of the provincial capital Karachi, during Friday Prayers.
The Sunni militant group Jundallah claimed responsibility for the attack.
Sunni Muslim extremists have often targeted religious institutions of Shi'ites, whom they do not consider to be true Muslims.
Mosh districts of Sindh have been relatively immune from sectarian attacks common in other parts of Pakistan. But prvicial capital Karachi, Pakistan's largest city and key port, is rife with criminal, ethnic, political and sectarian killings.
The attack in Shikarpur was one of the deadliest in Pakistan since Taliban militants seized a mlitary-run school in the northern city of Peshawar on December 16 and killed 151 schoolchildren and teachers.