The Upper Dir area lies outside of Pakistan's tribal region but it is remote and dangerous

About 200 fighters have attacked a police check post in Upper Dir District, in the Khyber Pakhtunkhwa province of northwest Pakistan, killing seven and injuring many others.

Bahadur Khan, a local police official, said that Wednesday's attack began around noon. And according to reports, there are ongoing clashes between police and the fighters, who crossed into Pakistan from Afghanistan.

However, it was not clear if the fighters were Afghans or Pakistanis.

"The fighting is going on. They are resisting with full force," Rahim Gul, a police official told AFP by telephone from the nearby Barawal police station.

"They are in the hundreds and very well armed with light and heavy weapons. The area is remote and surrounded by mountains," he said.

Initial contact by radio had been lost, but he said helicopter gunships had been mobilised to try to put down the attack, with around 40 local and tribal police resisting on the ground.

The attack is the latest bloodshed as the Pakistani Taliban and affiliated groups carry out threats to avenge the May 2 US raid that killed Osama bin Laden in Pakistan's northwest.

But it is more likely a reaction to ongoing Pakistani military offensives against insurgents along the border.

Although upper Dir lies just outside of Pakistan's tribal areas, it too has witnessed operations carried out by al-Qaeda and Taliban and counter-offensives by the Pakistani military.

The area is remote and dangerous, making it difficult to independently verify information.

The US has lauded Pakistan's operations against insurgents, which have been carried out primarily in the semi-autonomous tribal areas and targeted militants attacking the Pakistani state.

But Pakistan has, at least publicly so far, resisted American appeals to stage an offensive in the North Waziristan tribal area -  the primary haven for militant groups that attack US and NATO forces across the border in Afghanistan.

Source: Al Jazeera and agencies