KABUL, Afghanistan - NATO said yesterday that its forces killed scores of insurgents who had crossed from Pakistan in the biggest battle of the Afghan winter, while Pakistan's army fired artillery at trucks supplying extremists on the other side of the border.

NATO tracked the suspected Taliban insurgents through air surveillance while the fighters were still in Pakistan. Once they had crossed the frontier, NATO and Afghan soldiers attacked the two groups with ground fire and air strikes during a nine-hour battle that began Wednesday evening.

Gen. Murad Ali, the Afghan army regional deputy corps commander, said the insurgents had moved into Afghanistan's southern Paktika province with several trucks of ammunition. Lt. Col. Paul Fitzpatrick, a U.S. military spokesman, said it was likely they planned to carry out an immediate attack, given the size of the groups.

Taliban insurgents launched a record number of attacks in Afghanistan last year, and an estimated 4,000 people died in insurgency-related violence. Afghan and Western officials say the insurgents operate from sanctuaries in Pakistan; the Pakistani government insists it does all it can to stop them.

The overnight offensive in Paktika province was the first major engagement of 2007 and appeared to be the largest battle since September, when an operation that lasted several days killed more than 500 Taliban fighters in southern Kandahar province.

Fitzpatrick said 130 fighters were killed or wounded in the attack, down from NATO's initial estimate of as many as 150 dead. The Afghan Defense Ministry put the death toll at 80.

It was not clear why there was such a disparity in the estimates. As is common in Afghanistan, independent confirmation of the death toll at the remote battle site was not immediately possible.

Fitzpatrick said commanders lowered the estimate after further evaluating reports from observers that were made at night under difficult conditions. In early December, NATO said it had killed 70 to 80 fighters in Helmand province, but days later said only seven or eight had died.

Muhammad Hanif, who claims to speak for the Taliban, said in a text message to an Associated Press reporter in Pakistan that the initial NATO figure was "a complete lie."

"The Americans want to boost morale of their troops while making such claims," the message read.

The Pakistani military has several checkpoints in the area where the insurgents crossed the border with Afghanistan.

Pakistani army spokesman Maj. Gen. Shaukat Sultan said the attack on the insurgents' trucks Wednesday night showed the army could act swiftly and effectively if given "real-time" intelligence.

"We don't deny that some people are coming from this side," he said. "That's why we seek intelligence in real time. We are keen to stop it."

It was the Pakistani army's first reported offensive in the North Waziristan tribal region since a September peace deal between the government and pro-Taliban extremists that critics say has provided a sanctuary for insurgents.