Pakistani troops, artillery and helicopter gunships hit targets in the country's tribal areas on Thursday, officials said, in a second day of military action against Taliban insurgents.
The attacks in North Waziristan, a militant stronghold on the Afghan border, destroyed hundreds of shops and houses, officials said.
They came a day after air strikes and ground fighting killed at least 71 suspected militants 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 towards the garrison town of Bannu in neighbouring Khyber Pakhtunkhwa due to the unrest.
The violence comes as another blow to peace talks between the government and the Tehreek-e-Taliban Pakistan (TTP), which 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 AFP on the second day of clashes.
The official said a curfew had been imposed in the whole 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 added that troops on the ground had begun a door to door search operation for militants.
“Troops also used explosives to blow up more than 100 houses belonging to militants in Maachis Camp,” the official said, referring to the neighbourhood on the outskirts of Miranshah which was once a camp for Afghan refugees but is now thought to be used by militants.
In the nearby town of Mir Ali, the military also targeted militant hideouts and helicopters fired shells on suspected hide outs.
“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 militant hideouts in North Waziristan, from where they launch attacks against US 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. - Sapa-AFP