There are roughly 40-45 soldiers per platoon.
Clashes with police
In Buner, one policeman was killed and another wounded when unidentified men opened fire on their vehicle, which was being escorted by paramilitary forces, Syed Azhar, a police officer, told AFP on Thursday.
Several Taliban fighters occupied a police post and vacated it after some time, taking a police inspector with them, Rashid Khan, another police officer, said.
A meeting between tribal elders and the Taliban in Daggar, Buner's main town, ended without any indication that the Taliban would withdraw.
Daggar's bazaar as well as the road into the district were almost deserted, according to an AP Television News reporter who visited the area and witnessed part of the meeting.
Some fighters have also moved into Shangla, a district adjoining Buner, Fazal Ullah, a local politician, told AFP.
Elsewhere in the region, troops reportedly killed 11 fighters and destroyed 11 hideouts in the tribal district of Orakzai where the Taliban is active.
In a separate incident, fighters attacked a depot for Nato fuel tankers in Peshawar, capital of North West Frontier Province, and fled after destroying six of the vehicles, police said.
Alarm in Washington
Taliban fighters have moved into Buner from the neighbouring Swat valley, where Asif Ali Zardari, the Pakistani president, signed a deal into law in April allowing the implementation of strict Islamic law in an attempt to end an armed revolt.
Pervez Musharraf, the former Pakistani president, said on Al Jazeera's Frost Over The World programme that he believed it was wrong for Pakistan's current government to introduce sharia in Swat.
"There is a legal system functioning in Pakistan. Whatever you do in Swat must be within that legal system," Musharraf said.
"If the same people are demanding things beyond that ... and they start adopting measures punishing people for things that a moderate person would not think is tolerable, that becomes challenging to the weight of the government."
The pact has also caused alarm in Washington, where Robert Gates, the defence secretary, said Pakistani leaders must take the necessary actions to stop the threat posed by Taliban.
"It is important they not only recognise it (the threat) but take the appropriate actions to deal with it," he said on Thursday.
"The stability and longevity of democratic government in Pakistan is central to the efforts of the coalition in Afghanistan and it is also central to our future partnership with the government in Islamabad."
"We want to support them. We want to help them in any way we can. But it is important that they recognise the real threats to their country."
Hillary Clinton, the US secretary of state, earlier said the Taliban advances posed an "existential threat" to the survival of Pakistan.
"I think the Pakistani government is basically abdicating to the Taliban and the extremists," she told congress members in a hearing in Washington on Wednesday.
But on Thursday she said she thought Pakistan was beginning to recognise the severity of the threat posed by the group.
Clinton told a House of Representatives Appropriations subcommittee that the Obama administration was working to convince the Pakistani government that its traditional focus on India as a threat had to shift to Muslim fighters.
"Changing paradigms and mindsets is not easy, but I do believe there is an increasing awareness of not just the Pakistani government but the Pakistani people that this insurgency coming closer and closer to major cities does pose such a threat," she said.
Tariq Fatemi, Pakistan's former ambassador to the US, told Al Jazeera the Swat deal had been "deeply disappointing" to a large number of people in Pakistan as well.
"Most of us, including myself, see the manner in which this particular deal has taken place as an abandonment of government responsibility [and] as a surrender to a group of individuals who virtually had their guns on the temples of the government leadership," he said.
Separately, Richard Holbrooke, the US special envoy to Pakistan and Afghanistan, called Zardari to discuss the situation in the region, Zardari's office said without specifying if Buner was mentioned.
The call came as Admiral Mike Mullen, the chairman of the US joint chiefs of staff, was in Pakistan for talks with officials.
Seeking to allay US concerns, Yusuf Raza Gilani, Pakistan's prime minister, said that the Swat peace deal was aimed at promoting peace in the region.
"Agreements are made so that both sides are bound by it. We have a minimum understanding that needs to be adhered to," he said.
"Our agreement was that there will be peace in Swat and in return we would give them speedy justice. We have said we will take part in political dialogue with those who put down their weapons and the writ of the government. But if those agreements are broken, then we reserve the right for other options as well."