About 150 people were wounded and some remained in critical condition after the bombing Friday in the southwestern city of Quetta, police official Mohammed Sultan said.
The attack was the second in a week against Shiites for which the Pakistani Taliban claimed responsibility. A triple suicide bombing Wednesday killed 35 people at a Shiite ceremony in the eastern city of Lahore.
"Our war is against American and Pakistani security forces, but Shiites are also our target because they, too, are our enemies," Pakistani Taliban commander Qari Hussain Mehsud told The Associated Press.
He said he was proud the U.S. had added the Pakistani Taliban to its international terrorism blacklist Wednesday and threatened attacks in coming days in the U.S. and Europe.
"We will prove that we have ability to strike right in their countries," Mehsud said.
Shiite leaders blamed the government for failing to protect them and called a general strike in Quetta, where all schools were closed for a day of mourning. Shiites make up an estimated 20 percent of the population in the mostly Sunni Muslim country, although figures are imprecise and disputed.
Long-standing sectarian violence in Pakistan, particularly against Shiites, has been exacerbated by the rise of the Sunni extremist Taliban and al-Qaida movements.
Interior Minister Rehman Malik said the Taliban, al-Qaida and the outlawed Lashkar-e-Jhangvi militant group were working together to destabilize Pakistan. "They are infidels," he told reporters in Islamabad.
Meanwhile, two U.S. missiles fired from unmanned aircraft hit a house and a vehicle Saturday evening in a village near Miran Shah, the main town in the North Waziristan tribal region, officials said. The attack killed seven militants, four of them foreigners, they added.
The two intelligence officials spoke on condition of anonymity because they were not authorized to release the information to the media.
Two airstrikes in the region Friday killed seven people, two believed to be foreign militants, they said.
Pakistan's weak civilian government is struggling to deal with massive flooding and the incessant militant violence aimed at overthrowing the Western-backed administration.
White House press secretary Robert Gibbs said the timing of the recent attacks -- during the Muslim holy month of Ramadan and as Pakistan recovers from the flooding -- made them "even more reprehensible."
The U.N. humanitarian affairs office reported new flooding around the town of Dadu near the Indus River in Sindh province, about 200 miles (330 kilometers) from the Arabian Sea.
Flood-related health problems continued to increase despite receding waters in many parts of the country. The World Health Organization reported a spike in suspected malaria cases in Sindh and Baluchistan provinces, while diarrhea and acute respiratory diseases such as pneumonia continue to plague the disaster zone. More than 4.5 million people have received medical help since the flooding began in late July.
Between 600,000 and 800,000 people have been displaced over the past four days and three towns were under water. About 150,000 people were waiting on a road for assistance, according to what the U.N. described as rough estimates from staff and local officials in the area.
At least 3.5 million people in Sindh and 6.5 million nationwide have been displaced. "The monsoon season has ended, fresh flooding has not," U.N. spokesman Maurizio Giuliano said.
The flooding began with unusually heavy rains in the country's northern mountains and killed more than 1,600 people. Millions have been driven from their homes and the waters are still swamping rich agricultural land in the southern provinces of Sindh and Punjab.