At least 67 people have died and 180 been injured in a bomb blast which ripped through a marketplace in Quetta, southwest Pakistan.
The explosion destroyed shops in the residential suburb and caused a two-storey building to collapse. Police say some victims may still be buried by rubble.
they also say many of the maimed remain in a critical condition, and that the blast was targeted at Shiite Muslims, who mostly populate the neighbourhood.
It was the deadliest incident in the country since a series of bombings in January killed 86 in the same city. That attack led to days of protests that eventually toppled the local government.
Shiites, a minority in the Sunni-dominated country, have been increasingly attacked by militant groups who view them as heretics and non-Muslims.
Quetta's police chief, Zubair Mahmood, told reporters the bomb was hidden in a water tank which was towed into the market by a tractor.
Police do not yet know who was behind the bombing but a local television station reported that Lashker-e-Jhangvi, a Sunni extremist group that has targeted Shiites in the past, had called to claim responsibility.
Senior police officer Wazir Khan Nasir said the bomb was detonated by remote control.
Another officer, Samiullah Khan, said dozens of women and children were buying produce for their evening meal when the attack happened. Local residents rushed the victims to three different hospitals.
After the blast, members of the Shiite community took to the city streets in angry protest, blocking roads with burning tyres and throwing stones at passing vehicles.
Some fired bullets into the air to deter others the area in case there was another explosion. Insurgents sometimes stagger the explosions to kill people who rush to the scene to help.
Many of the Shiites in Quetta are Hazaras, an ethnic group that migrated to Pakistan from Afghanistan more than a century ago. Speaking of Lashker-e-Jhangvi, Qayum Changezi, the chairman of a local Hazara organization, said: “This evil force is operating with the patronage of certain elements in the province.”
Most of those killed in both recent attacks were Hazaras. Last time, residents protested against the government's response by refusing to bury their dead for days, camping out on the streets with the bodies in coffins.
After days of protests, Prime Minister Raja Pervaiz Ashraf flew to the city to meet protesters and sacked the chief minister and his cabinet.
Quetta is the capital of Baluchistan province, where nationalist groups are fighting an insurgency, trying to gain a greater share of income from its gas and mineral resources. Islamic militants are also active.
Last year was particularly deadly for Shiites in Pakistan. According to Human Rights Watch, more than 400 were killed in targeted attacks across the country.