Pakistani Shiite Muslims hold placards during a protest against a bombing Saturday that killed 89. Demonstrators want the government to do more to protect them from Sunni extremists. (BANARAS KHAN/AFP/GETTY IMAGES)

Thousands of Shiite protesters across Pakistan on Tuesday refused to back off from their demands that the government do more to protect them from rising attacks by Sunni extremists — rejecting official overtures earlier in the day that included a paramilitary sweep against the militants behind two massive bombings in Shiite neighborhoods in the southwestern city of Quetta.

The demonstrations paralyzed major transit hubs Tuesday night, blocking roads leading to the international airports in Lahore and Islamabad and obstructing access to a train station in Karachi, according to television broadcasts.

Earlier Tuesday, responding to the fury of the long-persecuted minority Muslim sect, Prime Minister Raja Pervez Ashraf sent a delegation to Quetta to meet with Shiite family members who have refused to bury the bodies of the victims of Saturday’s bombing, which killed 89 people. The protesters, who have staged sit-ins for three days, say only a concerted operation by the country’s powerful army can root out Lashkar-e-Jangvi, a banned militia that has claimed responsibility for Saturday’s bombing and a January blast that killed more than 90 people.

Lashkar-e-Jangvi’s attacks have focused on ethnically Hazara Shiites, whose distinctive features have made them easy targets. Sunni militant groups do not consider Shiites to be Muslims.

The government said Tuesday that security forces had killed four men behind attacks on Hazaras and had arrested 170 alleged militants in Quetta. It also dispatched a team to hold talks with Shiite leaders.

“I assure the people of the Hazara community that this operation will continue until the elimination of all terrorists,” Qamar Zaman Kaira, Pakistan’s information minister, told journalists.

But the paramilitary sweep, carried out by the Frontier Corps, fell short of the Hazaras’ demand for the deployment of the army in Quetta, the capital of Balochistan province. Shiite leaders who had urged mourners to peacefully go home faced resistance from families who said the government’s promises were not good enough.

Hazara leaders said Islamabad ignored their pleas for protection last summer, months before the first Quetta bombing in January, when Lashkar-e-Jangvi set off explosives in a Shiite neighborhood.

Some critics said the weak civilian government resorted to typical knee-jerk reactions to temporarily ease the problem of sectarian violence, which it had ignored for years. The political leadership in Pakistan almost always bows to pressure from the army, which has said its resources are too strained by fighting a Taliban insurgency to launch new operations.

“One major problem that I see with this government is the lack of political will to opt for sustained measures against the terrorists,” said Hasan Askari Rizvi, a security analyst.