Thousands of Shi'ite Muslims rallied January 31 in Pakistan to protest the killing of 61 people in a suicide bombing at a mosque, in the nation's worst sectarian attack in nearly two years.
The blast on January 30 hit the mosque in the Shikarpur district of the southern Sindh province, around 470 kilometers north of Pakistan's biggest city Karachi, as hundreds of worshippers attended Friday Prayers.
Police said on January 31 that the blast was caused by a suicide bomber who detonated the explosives strapped to his body "in the middle of the mosque."
Police said the bomb was loaded with steel pellets, ball bearings, and other shrapnel to cause maximum damage.
The provincial government declared January 31 a day of mourning, closing schools, shops, and offices, with no public transport available on the roads.
In Shikarpur, thousands gathered to attend funeral prayers for the dead. Shi'ite mourners beat their chests and heads, wailing as other non-Shi'ites also took part.
Karachi, Pakistan's economic heart and Sindh's provincial capital, also shut down for the day, with hundreds of Shi'ites staging protest rallies.
Shi'ite organizations also held protest sit-ins in various cities across Pakistan. Television footage showed some demonstrators burned tires and blocked roads, chanting slogans for the arrest of the perpetrators and protection for Shi'ite worship places.
Prime Minister Nawaz Sharif, speaking at a military event in Lahore, vowed step up efforts "to fight against terrorism."
UN Secretary-General Ban Ki-moon said in a statement he was "appalled by such vicious targeting of people on account of their religious affiliation."
A spokesman for the shadowy Jundallah militant group, a splinter faction of the Pakistani Taliban, claimed responsibility for the Shikarpur attack.
Jundallah has previously claimed responsibility for attacks on Shi'ites and other religious minorities, including a 2013 double suicide bombing of an Anglican church in Peshawar that killed 85 people.
Pakistan has seen a rising in sectarian violence in recent years, most of it perpetrated by hardline Sunni Muslim groups against minority Shi'ites, who make up around 20 percent of the population.
Friday's bombing was the bloodiest single sectarian attack in Pakistan since March 2013, when a car bomb in a Shi'ite neighborhood of Karachi killed 45.
Some 1,000 Shi'ites have been killed in the past two years in Pakistan, with many of the attacks claimed by the hardline Sunni group Lashkar-e-Jhangvi.