Fierce fighting is taking place in South Waziristan as Pakistani troops battle to gain control of the important militant-held town of Kotkai.
The army said it had secured the heights around Kotkai, the home town of top Taliban leader Hakimullah Mehsud.
Up to 100,000 civilians have fled the conflict zone, according to the army.
The army says it has killed nearly 80 militants so far. The Taliban deny the claim. Journalists are denied access to the area and cannot verify the reports.
Soldiers are reported to have briefly taken control of Kotkai in the course of fighting overnight.
But on Tuesday morning the Taliban hit back, destroying army checkpoints and killing seven soldiers, local officials said.
The officials said four Taliban militants were also killed – a claim the Taliban deny. The militants say they have yet to lose a single fighter.
Kotkai is also the home of senior militant commander, Qari Hussain, the man reportedly responsible for training Pakistani Taliban suicide bombers.
Propaganda war
Fighting is in its fourth day across much of South Waziristan. Both sides are using heavy weapons to bombard each other’s positions, the BBC’s Syed Shoaib Hasan in the nearby town of Dera Ismail Khan said.
The army has put up checkpoints in Manzai in the west, Jandola in the east, Razmak in the north and Wana in the south-west.
The army and the Taliban are also engaged in a propaganda battle for the sympathies of the Mehsud tribe – about two-thirds of South Waziristan’s population are Mehsuds.
The military says it has dropped leaflets from helicopters urging Mehsud tribesmen to rise up against the militants and to support the government offensive.
But a statement issued by the Taliban to the BBC warned Mehsud tribesmen of retaliation if they supported the government.
“We also call on the Mehsud and their leaders not to support or speak in favour of the government. If any Mehsud tribesman helps the government or speaks in their favour, strict action will be taken against them,” Taliban spokesman Azam Tariq told the BBC.
Civilian exodus
The fighting in South Waziristan has caused tens of thousands of civilians to flee.
The flow of refugees was unabated on Tuesday and about 8,000-10,000 people were expected to register themselves as displaced, social welfare officials told the BBC.
But officials have warned of several difficulties in setting up camps for those displaced.
A shortage of registration forms meant that new arrivals were not being offered aid and the conservative social customs of the people pouring out of the region also presented difficulties in accommodating them, officials said.
About 10,000 people from Waziristan are also reported to have fled south to the neighbouring Pakistani province of Balochistan. Reports say that until now no aid agency had been aware of their arrival in the region.