NATO and Afghan troops killed up to 150 insurgents in a ground and air operation in southeastern Afghanistan after the insurgents infiltrated into Afghanistan from neighboring Pakistan, the alliance said Thursday.

Afghan anger over the infiltration of Taliban militants from Pakistan has seriously soured relations between the neighbors, both important US allies in the war on terrorism.

The latest fighting, the biggest clash in Afghanistan in months, was on Wednesday night in the Bermal district of Paktika province, bordering Pakistan, NATO said.

"Two large groups of insurgents were observed infiltrating Paktika province from Pakistan," the alliance said in a statement.

"The insurgents were monitored, tracked and subsequently engaged in Afghanistan, through the coordinated use of both air and ground fire in a series of engagements along the sparsely populated border region," it said.

NATO said initial battle damage estimates indicated as many as 150 insurgents were killed. It did not say if there were any casualties among NATO or Afghan government troops.

NATO said Pakistani military liaison officers were kept fully informed throughout the operation.

Last year was the bloodiest since US-led forces overthrew the Taliban in 2001. More than 4,000 people, including nearly 170 foreign troops, were killed.

Most of the violence has been in southern and eastern areas bordering Pakistan.

Afghanistan says the militants have sanctuaries in Pakistan from where they launch attacks across the border.

Pakistan was the main supporter of the Taliban until the September 11 attacks on the United States. It denies any official help for the Taliban but says some militants are crossing into Afghanistan from Pakistani tribal lands where Pakistani forces have been battling militants.

Pakistan had repeatedly assured Afghanistan it would take action against the militants.

(China Daily via agencies January 12, 2007)