The Pakistani military came to the aid of citizen militia groups fighting the Taliban in the northwest on Tuesday by providing supporting fire and helicopter gunships.

Citizens near the Swat Valley formed a militia group — also known as a lashkar — on Saturday in order to strike back at the Taliban, who bombed a mosque in the neighbouring Upper Dir district on Friday.

The militia group, outraged over the attack that killed at least 33 worshippers, began fighting the Taliban two days ago. Their numbers have grown from 500 when initially formed to over 2,000, as men from two villages and a town joined the group Tuesday, according to a local police official.

"People back in the villages, especially children, are fetching them food and other supplies. They are doing it because they think the fighters are fighting for their sake, they think it is their common war," police official Atlas Khan said.

At least 14 insurgents have died since fighting began on Saturday.

Militias encouraged

The government has encouraged citizens to set up militias to oust Taliban fighters, especially in the regions that border Afghanistan where al-Qaeda and the Taliban have hideouts. But villagers' willingness to do so has often hinged on confidence that authorities will back them up if necessary.

The army has been reluctant to support militias with heavy fire for fear of hitting the citizen fighters, who were engaged in close combat with Taliban forces.

Khan confirmed media reports that helicopter gunships struck two villages, Shatkas and Ghazi Gay, where the militants have strongholds, late Monday and Tuesday morning.

"Lashkar men are positioned on surrounding mountains and keeping a vigil on the movement of Taliban militants," one military official who requested anonymity told the Agence France-Presse news agency.

Some of the Taliban were blocked Tuesday when they tried to get away to nearby Malik Bai village, which the tribesmen also encircled, police said.

"Villagers have encircled them completely, and they cannot run away," said Upper Dir district police Chief Ejaz Ahmad.

Asked how long the fight might go on, the police chief said, "The militants are well-entrenched in their strongholds. The area is large and consists of tough terrain, which also has thick forests. I cannot say when, but it will take time to expel or kill all the militants completely."

Shelling in Bannu

Meanwhile, the military started shelling in the Bannu district, about 220 kilometres south of Dir.

The military pummelled the tribal-controlled area of Jani Khel in Bannu after tribesmen refused to hand over Taliban militants taking refuge there, senior local government official Kamran Zeb Khan said.

Military spokesman Maj.-Gen. Athar Abbas did not confirm the shelling, but said an operation was planned in the area against Taliban blamed for the recent hijacking of a convoy of military college students. The students were all freed.

Earlier, the BBC reported that officials had imposed a curfew in Bannu, an area bordering the Taliban stronghold of Waziristan.

Troops are massing at the border between Bannu and Waziristan, which is where several high-profile insurgents — among them al-Qaeda head Osama bin Laden, his deputy, Ayman al-Zawahiri and Pakistani Taliban chief Baitullah Mehsud — are believed to be hiding.

Possible Waziristan strikes

Local officials say citizens are leaving the area in preparation for what they believe will be a military strike on Waziristan.

No plans for an operation in South Waziristan have been announced, and the military has refused to comment directly. Connecting the Bannu operation to a possible broader offensive in the Waziristan districts was "speculation," Abbas said.

U.S. officials have said privately they would like Pakistan to follow up the Swat offensive by launching an operation in the nearby South Waziristan tribal region.

The month-old Swat offensive, the latest round in a valley that has experienced fighting for two years, is seen as a test of Pakistan's resolve to take on al-Qaeda and Taliban fighters on its soil.

The U.S. hopes the offensive will eliminate a potential sanctuary for militants implicated in attacks on Western forces across the border in Afghanistan.

The military says more than 1,300 militants and 105 soldiers have died so far in the offensive. The Taliban have threatened to stage suicide attacks in major Pakistani cities in revenge for the Swat operation.

With files from The Associated Press