Heavy casualties inflicted by U.S.-led coalition forces have forced Afghan rebels (search) to recruit younger fighters and change their tactics, but the insurgency is far from broken, a U.S. military spokesman said Monday.

Four years after U.S.-led forces drove the hard-line Taliban from power, insurgents are no longer able to carry out large-scale attacks and have resorted to payments and threats to bring younger men into a fighting force that is not centrally coordinated, Col. James Yonts said.

"What we are seeing is a change in tactics," Yonts said. "They no longer have that pool of resources that they can mount a serious offensive against us."

Instead, he said, small pockets of insurgents are resorting to roadside bombs, often targeting civilians, and harassing attacks on police posts.

"You see a hit-and-run approach instead of major combat operations," he told a news conference in the wake of Sept. 18 legislative elections that went off without major rebel attacks.

A rejuvenated Taliban insurgency has led to the deaths of more than 1,200 people in the last six months — many of them rebels killed in fighting with the 20,000-strong U.S.-led coalition force and the fledgling Afghan security forces (search).

"They have changed their normal operations and included a different kind of combat soldier," he said, adding that coalition forces are seeing fewer "hard-core" fighters. "We also do not see a lot of the seasoned, trained leadership as much as we had in the past."

Yonts said insurgents are recruiting fighters by paying them or threatening them or their families, as well as relying on militants who recently arrived from outside Afghanistan — through he would not say where they were coming from.

President Hamid Karzai (search) has suggested militants come from Pakistan, which Islamabad vehemently denies.

"We are seeing a very young, inexperienced, lack of leadership type of force," Yonts said. "There doesn't seem to be any overarching or underlying infrastructure between these elements that we're fighting here. It appears to be pockets of small numbers."

Yonts said coalition and Afghan forces "are winning this battle."

"Afghanistan is much more secure than it was two years ago, but there's still an enemy out there," he said. "The war is not over. They're still there and they're still armed, resourced, well-equipped, fed. So you've heard the term 'broken back' or 'on the ropes' — far from it. We don't see that at all."

U.S. National Security Adviser Stephen Hadley said Monday that Afghanistan, Pakistan and the United States needed to cooperate more closely to stem the threat from terrorists based in Pakistan's border areas.

"There are people in the border areas of Pakistan (search) that threaten my country, threaten Pakistan and threaten Afghanistan. All three of us are threatened, and all three of us have to cooperate in the solution," Hadley said during a visit to Afghanistan.

"The three nations ... need to share intelligence and take, as much as possible, joint action to deal with this threat," he said.