Prime Minister Raja Pervez Ashraf arrived Sunday in the southwestern city of Quetta to meet Shiite Muslim families refusing to bury their dead after devastating bombings, officials said.
At least 92 people were killed and 121 wounded Thursday in twin suicide attacks claimed by Lashkar-e-Jhangvi in an area dominated by Shiites from the Hazara ethnic minority.
It was the worst ever sectarian attack on Shiites in Pakistan.
Shiite families have refused to bury their dead and vowed to continue a sit-in protest with thousands of others until the army takes over security in the city. They have been sitting in the open with the bodies for the past 48 hours.
Refusal to bury the dead is an extreme protest in Islamic society, where the deceased are normally buried the same day or the next day.
But families say they will not leave until the authorities agree to put the security and administration of the city under army control.
"Prime Minister Raja Pervez Ashraf has arrived in Quetta, he will meet the leaders of the Hazara community," a senior government official told AFP on condition of anonymity.
An AFP reporter said up to 8,000 people including women and children had gathered at the protest and faced a cold night in the open with the coffins of more than 60 of the dead.
"Quetta has become a killing field and we are protesting to stop target killings," said a protester who identified himself as Ali Raza.
"None of my relative was killed, but I am here to support the families who have lost their loved ones, and they have been sitting in the open in this harsh weather for the past 48 hours," Raza said.
Nadir Ali, an elder of the Hazara Shiites, said the prime minister should sack the provincial government and impose federal rule in Baluchistan province, of which Quetta is the capital, handing over security to the army.
"We will not hold talks with anyone from the provincial government because they have never listened to us in the past despite a spate of killings. We will talk to the prime minister only and demand imposition of governor's rule," he said.
Rallies were held in several cities including Karachi, Lahore, Multan, Gujranwala, Muzaffarabad and Rawalpindi to express solidarity with the Hazara community, and several political parties marked Sunday as a day of protest.
The government in Baluchistan province announced three days of mourning after the bombings outside a snooker hall.
It was the deadliest attack of any kind in Pakistan since suicide bombers killed 98 people outside a police training centre in the northwest in 2011 -- an assault claimed by the Pakistani Taliban.