Pakistani soldiers have entered the main town in the Swat valley and engaged in fierce street battles with Taliban fighters, the military has said.
Major-General Athar Abbas, a Pakistani military spokesman, said on Saturday that troops had killed at least 17 Taliban fighters as they moved into in Mingora.
Al Jazeera's Imran Khan, reporting from the capital, Islamabad, said that the urban battles now being fought by the Pakistani infantry marked a new phase in the conflict in North West Frontier Province.
"The army is telling us that street fighting will be one of the key phases of this battle for Mingora, so far they have used heavy artillery and air power to pound Taliban targets," he said.
"They say they have already taken control of a main bridge into Mingora and they have also taken control of the main interchange. The battle, they say, is going their way.
"But the Taliban know this area very well and it is likely they will have been preparing for this moment for some time. It is likely they will have built tunnels and will know exactly what rooftops to get on."
'Important phase'
There were reports that troops had captured and destroyed an explosives-laden vehicle in the early stages of the fighting.
Mingora, the administrative and business hub of Swat, has been under the effective control of Taliban fighters for weeks.
Civilian fears
Many of the 300,000 people who live in Mongora are believed to have fled since the military began its offensive in Swat, Lower Dir and Buner several weeks ago.
Abbas said that only 10 per cent of the population remained in the town, but the street-to-street has raised the possibility of civilian casualties.
The offensive in Swat and surrounding areas in the North West Frontier Province (NWFP) has triggered an exodus of nearly two million refugees from the region.
While some of those displaced have taken refuge in government camps, a majority of them have taken shelter with friends and relatives.
The military has said it had inflicted heavy losses on the Taliban, with about 1,000 fighters reported to have been killed.
PHOTO CAPTION
Pakistani soldiers stand guard on top of a mountain overlooking the Swat valley at Banai Baba Ziarat area in northwest Pakistan.
Agencies