QUETTA, Pakistan – A bomb hidden in a water tank ripped through a crowded vegetable market in a mostly Shiite neighborhood in a southwestern Pakistani city Saturday, killing at least 65 people and wounding nearly 200, officials said.

Police said many of those wounded in the explosion in Quetta remain in critical condition. The blast, which police said targeted the country’s minority Shiite Muslim sect, left many victims buried under rubble, but authorities did not know how many.

It was the deadliest incident since bombings targeting Shiites in the same city killed 86 people earlier this year, leading to days of protests that eventually toppled the local government.

Shiites have been increasingly attacked by militant groups who view them as heretics and non-Muslims in this Sunni Muslim-dominated country.

Many of the Shiites in Quetta, including those in the neighborhood attacked Saturday, are Hazaras, an ethnic group that migrated to Pakistan from Afghanistan more than a century ago.

Quetta police chief Zubair Mahmood told reporters that the bomb was hidden in a water tank and towed into the market by a tractor. He said the blast destroyed shops in the neighborhood and caused a two-story building to collapse.

“We fear some victims may be found buried there,” he said.

Mahmood said police did 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, set off in a residential suburb, was detonated by remote control.

Another officer, Samiullah Khan, said the bomb was detonated while dozens of women and children were buying produce for their evening meal.