Pakistani troops, artillery and helicopter gunships hit targets in the country's tribal areas Thursday, officials said, in a second day of military action against Taliban fighters.
The attacks in North Waziristan, an insurgent stronghold near the Afghanistan border, destroyed hundreds of shops and houses, officials said.
The latest offensive came a day after airstrikes and ground fighting killed at least 71 suspected Taliban fighters and four security officials in the same area.
It was not clear how many people were killed or wounded in Thursday's raids, but local residents and officials said thousands had started fleeing toward the nearby garrison town of Bannu due to the unrest.
The violence comes as another blow to peace talks between the government and the Tehreek-e-Taliban Pakistan (TTP). The talks have made little progress since they began in February.
Troops backed by tanks, helicopter gunships and reconnaissance drones swung into action on Thursday, destroying shops and houses, local residents and officials said.
"Shelling is continuing since overnight as military has launched a search operation in Machis Camp," a local government official told Agence France-Presse on the second day of clashes.
The official said a curfew had been imposed on all of North Waziristan.
"Artillery and helicopter gunships are targeting militant hideouts," a local intelligence official in Miranshah, the main town of North Waziristan, told AFP.
He said that troops on the ground had begun a door-to-door search operation for insurgents.
"Troops also used explosives to blow up more than 100 houses belonging to militants in Machis Camp," the official said, referring to the neighborhood on the outskirts of Miranshah, which was once a camp for Afghan refugees but is now thought to be used by insurgents.
In the nearby town of Mir Ali, helicopters fired shells on suspected hideouts.
"The troops have destroyed about 300 shops in the main Mir Ali bazaar," a local official told AFP.
Local residents also said that the main power cable to the area was damaged in shelling and there was no electricity supply in the area since the previous night.
On Wednesday air force jets began the onslaught, bombarding targets in North Waziristan before ground battles between troops and insurgents.
Washington has long pressured Islamabad to carry out an operation to stamp out insurgent hideouts in North Waziristan, where attacks are launched against U.S. and NATO troops in Afghanistan.
But it was not clear that the latest military action was the beginning of such an operation. The armed forces carried out similar strikes in January.
There have been a number of insurgent attacks on security forces in recent weeks, and the air raids and the current strikes fit a pattern of the armed forces responding by hitting the insurgents' bases in the tribal areas.
The TTP is a loose network of groups, some of them waging a war aimed at overthrowing the government and establishing their own hard-line version of an Islamic state.