The Upper Dir area lies outside of Pakistan's tribal region, but it is remote and dangerous [Al Jazeera]

At least 24 Pakistani security forces and three civilians have been killed in fighting in northwest Pakistan after about 200 armed men crossed over from Afghanistan and attacked a security checkpoint, a government official said.

Around 40 fighters have also been killed in the gun battles, which have been going on for 24 hours in a village in the Dir region, Ghulam Mohammad Khan, a top local government official, told the Reuters news agency on Thursday.

"We are preparing to evacuate 24 bodies from the village," he said, referring to police and paramilitary forces killed in the fighting that spread to a forest. Khan said he had no figures on casualties among the attackers.

Dawar Ali, a Dir police official, said army troops had arrived in the area to support security forces. He said more details on the battles were hard to come by because communications had broken down in the area.

The armed group had arrived in a pre-dawn operation on Wednesday, dressed in military uniforms, and killed one policeman.

Salman Bashir, the Pakistani foreign secretary, has raised the issue with Mohammad Umer Daudzai, the Afghan ambassador to Pakistan.

He "conveyed ... strong concern" to the ambassador and "stressed the need for stern action by the Afghan Army, US and NATO/ISAF forces in the area against militants and their hideouts in Afghanistan", a statement said.

The statement said that the matter had also been raised with the United States and NATO.

Revenge attacks

Pakistan's Taliban movement, which has close ties to al-Qaeda, has stepped up pressure on the US-backed government after vowing to avenge the killing of Osama bin Laden by US special forces on May 2 in Abbottabad.

It has stepped up suicide bombings, attacking paramilitary cadets, a naval base, a US consulate convoy and other targets.

After the bin Laden raid, the US reiterated its call for Pakistan to crack down harder on the Taliban and al-Qaeda, especially on attempts by these groups to cross over to Afghanistan to attack Western forces.

The US has lauded Pakistan's operations against insurgents, which have been carried out primarily in the semi-autonomous tribal areas and targeted armed groups 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 armed groups that attack US and NATO forces across the border in Afghanistan.

It is not clear which armed group had taken on security forces in Dir, but groups along the frontier are closely linked. The area is remote and dangerous, making it difficult to independently verify information.

Source: Al Jazeera and agencies