The Pakistani military says it has killed more than 80 fighters in heavy fighting against several thousand Taliban loyalists in the country's northwest.
As the fighting raged, tens of thousands of residents fled the Swat valley area of the North West Frontier Province (NWFP).
The army launched its major offensive on Wednesday, with reports of aerial support being used overnight into Thursday.
Al Jazeera's Sohail Rahman, reporting from the capital, Islamabad, said: "The military offensive has continued overnight and into Thursday ... our producers on the ground say the curfew in the region has been lifted and will be reimposed at midnight [18:00 GMT].
"The roads are blocked and there is very little transport for those fleeing the fighting, so they have taken to the roads on foot to reach IDP camps."
"We are also hearing reports of jet fighters being used - that will be the first time in this battle and, if true, it is a very worrying development."
As citizens escaped to camps for internally displaced people (IDP), a February peace deal between the government and the Taliban looked to be all but extinguished.
Kifayatullah, the eldest son of Sufi Muhammad, a regional leader who brokered the accord, was killed in a bombardment on Thursday in Lower Dir which, like the Swat valley, is in the Malakand division of the NWFP.
The deal had brought peace in return for the enforcement of sharia, or Islamic law, but with the collapse of the agreement the Pakistan army is fighting the Taliban in several areas - Swat valley, Buner and Lower Dir.
Describing the fighting on Thursday, a military official said helicopter raids preceded the ground incursion to re-take a forested region in Swat where a number of mines are sited.
"Security forces were being targeted from emerald mines. In retaliatory fire, 35 militants were killed," the military said in a statement on Wednesday.
Another 49 pro-Taliban fighters were reportedly killed in the neighbouring Buner district.
Rahman reported that three Frontier Corps paramilitaries were killed in a Taliban assault on a checkpoint in Lower Dir. Eleven others were captured.
The military spokesman said there were also reports of a number of civilian deaths.
The government said it was preparing to shelter up to 500,000 refugees, while the International Committee of the Red Cross (ICRC) warned of a mounting humanitarian crisis in the region.
The ICRC said that they were marshalling aid to provide for 120,000 people, but could no longer reach the areas most affected by violence.
|For Buner residents, what was once a place of peace has become a scene of war and horror
Laiq Zada, 33, who escaped from the Swat valley to a government-run tent camp, said: "It is an all-out war there. Rockets are landing everywhere.
"We have with us the clothes on our bodies and a hope in the house of God. Nothing else."
Al Jazeera's Kamal Hyder, in Peshawar the capital of NWFP, said: "We are getting reports that people desperate to get out of harm's way are now trying to run out of that area. Whatever transport they can get.
"While [the military's] objective is to neutralise the Taliban, the civilians are caught in the middle.
"The big question mark is how does the military expect to achieve its objective in a heavily populated area."
Khushhal Khan, the chief administration officer in Swat, said: "More than 40,000 have migrated from Mingora [Swat's main town] since Tuesday afternoon."
Many told stories of their deprivation at the hands of the Taliban and government attacks.
"They [the Taliban] killed my husband, they slit his throat after accusing him of spying," Zarina Begum, 40, said as she arrived by bus in Peshawar, Pakistan's main northwestern city.
"This is a time when people in Pakistan realise this has now turned into a war on Pakistan and for Pakistan"
"A mortar hit my house and, as a result, I lost one of my eyes. Please take me to hospital, I want medical treatment," she said.
The Taliban said on Wednesday that it was still in control of 90 per cent of Swat.
Muslim Khan, a Taliban spokesman, said: "If the government launches an operation against us, we will give them a fitting reply, which it will remember for a long time."
Imtiaz Gul, head of the Centre for Research and Security Studies, a think-tank in Islamabad, told Al Jazeera: "This is a time when people in Pakistan realise this has now turned into a war on Pakistan and for Pakistan.
"The Pakistani military is the key to winning this war ... There is quite a clear consensus within the Pakistani ruling elite that they need to act in unison, that they need to demonstrate to the world that they are sincere in this war against the militants, which are basically attacking the foundations of this country."