Separately, five others died when an explosion ripped through a house near the Afghan border, local officials said. Claims that it was a missile strike could not immediately be confirmed.
Pakistan's five-month-old civilian government has been plagued by violence and political instability since Pervez Musharraf was forced to resign as president two weeks ago, adding to the many challenges ahead in the Muslim nation of 160 million people.
The economy is sinking, power outages are common, there are food shortages, and many drivers cannot afford to fill up their tanks.
But with a string of suicide bombings, including one that left 67 dead near the capital, Islamabad, tackling extremism is a priority.
Leaders initially offered to hold peace talks with insurgents - something Musharraf also briefly tried before his ouster - but have since resorted to what some are calling all-out war.
Army spokesman Maj. Nasir Ali said at least 40 Taliban were killed Friday when fighter jets pounded militants in Swat Valley, which was a popular tourist destination not long ago.
A cache of ammunition exploded when it was hit in one of the strikes, he said, adding that ground troops were advancing into the region Saturday to root out other militant fighters.
Taliban spokesman Muslim Khan said eight of his men, including a local commander, were killed.
The violence followed news that Asif Ali Zardari, who seems poised to be voted Pakistan's next president in a Sept. 6 election by lawmakers, had moved into a tightly guarded government compound because of security fears.
His late wife, Benazir Bhutto, a two-time former prime minister and an outspoken critic of Islamic extremism, was assassinated in a Dec. 27 gun-and-bomb attack during a campaign rally.
Officials say that fighting in Swat and Bajur, a rumored hide-out of Osama bin Laden, have left nearly 500 militants dead in August alone. There are no separate statistics for civilians, but witnesses say dozens have died.
More than 200,000 others have been forced to flee their homes, most of them women and children, and are now living in desperate conditions in sweltering, mosquito-infested relief camps.
Human rights groups expressed concern Saturday about the rising violence.
Locals "insist there is no targeted operation against militants, rather it is a haphazard armed invasion on the people of Swat," Asma Jahangir, chairwoman of the Human Rights Commission of Pakistan, wrote in a letter to the prime minister.
"They have given numerous examples where militants could have been apprehended or attacks on civilians could have been averted had the security forces acted with diligence," she wrote.
In other violence Saturday, a blast ripped through a home in Wana, a main town in the South Wazirtistan tribal region, killing at least five militants, said Afzal Khan, a local official, who had no further details.
Army spokesman Major Murad Khan was also aware of the explosion, but could not confirm claims by two local intelligence officials that it was caused by a missile. They spoke on condition of anonymity because they were not authorized to speak to the media.
The Taliban, meanwhile, have threatened to intensify a campaign of suicide bombings unless military operations in the northwest cease. They have carried out three strikes in recent days, the deadliest on one of the country's largest weapons factories.
At least 67 people were killed in those twin suicide bombings and more than 100 others wounded, almost all civilians.