Pakistan's prime minister has flown to the southwestern city of Quetta to meet with the Shi'ite families holding a protest alongside the coffins containing the bodies of family members killed in one of the country's worst sectarian attacks.

Raja Pervez Ashraf flew to Quetta Sunday, the third day of protests, following the bomb blasts Thursday that killed nearly 100 people.

Refusal to bury the dead is an extreme protest in Islamic society, where the deceased are normally buried within hours of their deaths.

Police say the bombings targeted an area of Quetta occupied mainly by ethnic Hazaras, who are Shi'ite Muslims. The outlawed militant Sunni group Lashkar-e-Jhangvi claimed responsibility for the attacks.

A separate bomb blast Thursday in Quetta killed 12 people, mostly security personnel. Militant Baluch nationalists claimed responsibility for that attack.

Another explosion Thursday in northwestern Pakistan killed more than 20 Muslim missionaries.

Attacks on Pakistani Shi'ites have been increasing steadily. One Shi'ite leader in Quetta criticized Pakistan's army chief, General Ashfaq Kayani, for failing to halt the killings.

The violence and criticism of the government and security forces come as Pakistan is gearing up for national elections expected in a few months.

Shi'ites comprise about 20 percent of Pakistan's mostly Sunni Muslim population of 160 million people.