Critics also say Pakistan maintains a so-called "good Taliban, bad Taliban" policy in which it combats the Pakistani Taliban, who attack the state, but tolerates or supports the Afghan Taliban in order to maintain influence in the neighboring country.
The offensive marks the end of the government's policy of trying to negotiate with Pakistani Taliban militants instead of using force to end years of fighting which has killed tens of thousands of civilians and security forces.
It comes a week after the militants laid siege to Pakistan's largest airport in an attack that shocked the country and appeared to mark a turning point in the government's thinking about the offensive.
But the large military operation could spark a wave of bloody reprisal attacks, especially in places such as Karachi or Peshawar, where militants already have a sizeable presence.
Even before the airstrikes, residents in North Waziristan were leaving the area due to previous airstrikes and out of fear of a larger operation.
Nawal Khan Dawar from Mir Ali said he arrived in Bannu six days ago with his family after an air strike nearby destroyed several houses. He said he rented a house for his family but, without any work, he doesn't know how long they'll be able to stay. He said he's worried about other family members still in North Waziristan.
"We don't know what happening with them. We have not heard from them," he said.
Some of the displaced were even going to Afghanistan. Mubariz Mohammad Zadran, a spokesman for the provincial governor of Afghanistan's Khost province, said over the last two weeks at least 404 families have entered from North Waziristan.
Shahzad contributed from Islamabad.
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