ISLAMABAD, Pakistan (CNN) -- Hundreds of Pakistani villagers who have formed an anti-Taliban militia battled for the fourth day Tuesday to remove the Islamic militants from a region of northwest Pakistan.
A Pakistani woman holds a child Monday at a displaced persons camp. Millions have fled violence in the country.
The Pakistani military is supporting the militia, or "lashkar," in Upper Dir district on the request of local officials and tribal elders, military spokesman Maj. Gen. Athar Abbas told CNN.
Outraged over a suicide attack on a local mosque during Friday prayers, about 400 residents formed the militia early Saturday and began battling Taliban militants. The attack on the anti-Taliban mosque killed at least 40 people and wounded 80 others.
The militia has surrounded Taliban fighters in Shat Kas, a village where the Taliban have local support, according to officials in the Upper Dir district. The Taliban have dug into bunkers and are putting up a strong resistance, he said.
The fighting marks the first major battle between the residents of northwest Pakistan and Taliban militants.
At least 14 Taliban had been killed and four villagers had been wounded as of Sunday evening, according to local administrator Atif-ur-Rehman.
The militia has burned houses thought to be sheltering the militants, and both the militia and Taliban fighters are using heavy weapons, including rocket launchers and anti-aircraft weapons, Rehman said.
Pakistani military helicopters were called in Monday and Tuesday to strike Taliban positions from the air, local officials said. Abbas confirmed that the gunships were used to shell specific militant targets in Upper Dir, on the request of local officials.
There is a long history of Taliban presence in the area, including foreign fighters in leadership roles, local officials said.
Upper Dir is a part of the Swat Valley, where the Pakistani military has waged a monthlong operation against Taliban militants. The district had not been part of the ongoing military offensive until this week.
The United Nations has said an estimated 2 million Pakistanis have been displaced by fighting between the Pakistani military and Taliban militants.
Suspected Pakistani Taliban militants have carried out several attacks on civilian targets across Pakistan in recent weeks. The Taliban claimed responsibility for a suicide attack that killed 27 people in Lahore on May 27.
The militants threatened to continue attacking cities in Pakistan until the military ends its operations against Taliban militants. As a result, Pakistani authorities have increased security in Islamabad, Pakistan's capital city.
The military operation continued Tuesday with Pakistani forces taking up positions in the Bannu district of North West Frontier Province, Abbas said. A curfew has been established in Bannu as military forces shell militant positions along the route that leads through neighboring Waziristan to the Afghan-Pakistan border, local officials said.
The Jani Khel tribe of Bannu is suspected of facilitating the recent kidnappings of Razmak Cadet College students, as well as ongoing rocket and roadside bombing attacks, Pakistani military sources said.
There are concerns that the tribe may also be planning more attacks in North West Frontier Province, which has suffered several bombings on civilian targets in recent weeks, including Friday's mosque bombing in Upper Dir.
On Tuesday, a bomb exploded at a major hotel in Peshawar, the capital of North West Frontier Province, killing at least five people, the city's district coordination officer said.
CNN's Ingrid Formanek and Journalist Nasir Habib contributed to this report.