Islamabad: Pakistani security forces have killed 20 militants near the Afghan border, a security official said on Thursday, as tensions surfaced with the United States over how to tackle the Taliban and Al Qaida.

An intensifying insurgency in Afghanistan has piled pressure on Pakistan to go after militants operating from sanctuaries in remote enclaves on its side of the border. It has also led to a sharp increase in US strikes on militants in Pakistan.

The new government in Islamabad says it is committed to the campaign against militancy, launched after the September 11, 2001 attacks, but bans incursions by US troops.

In the latest fighting in the northwestern Bajaur region, Pakistani security forces backed by air strikes killed 20 militants in an attack on a militant stronghold in the village of Rashkai that began on Wednesday and went on through yesterday.

"Troops are advancing and there have been encounters. Troops are also engaging them with artillery," said military spokesman Major Murad Khan.

Another military official said four soldiers had been killed, and some Arabs were among the dead militants.

Troops have killed more than 600 militants in Bajaur since August, the government says.

Militants in Bajaur, where some analysts believe top Al Qaida leaders have been hiding, regularly cross into Afghanistan to attack Western troops and government forces there.

Violence in Afghanistan has soared over the past two years as Al Qaida and Taliban fighters have regrouped.

Brown to talk with bush

British Prime Minister Gordon Brown said he would hold talks with US President George Bush on a new strategy to deal with the lawless Pakistan-Afghanistan border.

"What's happening on the border between Pakistan and Afghanistan is something where we need to develop a new strategy," Brown said.

"The insecurity on the border and the porousness of the border is a problem for both countries," he added.

He said he would also discuss it with Pakistan's new civilian president, Asif Ali Zardari, who he said was scheduled to visit London "in the next few days".

The Pakistan High Commission in London could not confirm Zardari would visit.