The Taliban claimed responsibility. Maulvi Umar, a spokesman for Pakistani Taliban groups, told the Associated Press the attacks were in revenge for military airstrikes in Bajur, a militant stronghold near the Afghanistan border.
"The Wah factory is a killer factory where arms are being produced to kill our women and children," Umar said.
Similar bombings would be carried out in other major cities, including Islamabad, unless the operations were halted, Umar said.
Tanvir Lodhi, a spokesman for Pakistan Ordnance Factories, said 59 people were killed. A hospital official said 70 were wounded.
"There were bodies lying everywhere and wounded people soaked in blood were screaming for help," a witness told Reuters.
Meanwhile, the ruling coalition government, made up of rivals who were united primarily in their determination to force former president Pervez Musharraf from office, appeared veering toward collapse.
Musharraf, who had been a key supporter of the U.S. war on terrorism, resigned Monday to avoid impeachment following nearly nine years in power.
The two main parties have been unable to bridge key differences, like whether judges fired by Musharraf should be quickly reinstated and who should succeed Musharraf as president.
Musharraf fired dozens of Supreme Court judges last year to avoid legal challenges to his rule.
On Thursday, lawyers rallied in Lahore, again demanding that the deposed judges be restored. They chanted slogans and carried signs critical of Musharraf. Pictures of the former president and a U.S. flag were also burned.
Former Prime Minister Nawaz Sharif's party threatened Thursday to leave the ruling coalition unless the judges were quickly reinstated.
The coalition's biggest bloc, the Pakistan People's Party, appeared to be lining up smaller parties to keep control of parliament in case that happened.
"The future of this coalition is linked to the restoration of judges," Sharif's spokesman Sadiqul Farooq told the AP. "If the judges are not restored, we will prefer to sit on opposition benches.
Asif Ali Zardari, the leader of the Pakistan People's Party, is less enthusiastic. He has accused former chief justice Iftikhar Mohammed Chaudhry of being too political.
The coalition also must seek agreement on a candidate for the presidency. The new leader must be elected by lawmakers by mid-September.
The People's Party insisted that, as the largest party in the coalition, it has the right to choose the new head of state.
Though they have yet to name a candidate, party members were mentioning a candidacy for Zardari, who comes from the well-off southern province of Sindh.
Sharif's party was arguing for a president from one of the smaller province in order to strengthen Pakistan's strained federation.