Kabul, Afghanistan ? The American military stepped up efforts to find Osama bin Laden and destroy his al-Qaida and Taliban supporters, announcing Saturday a major new sweep across lawless southern and eastern Afghanistan involving thousands of troops.

The military insisted their net will eventually close on the al-Qaida leader, who has vanished since melting into the Afghan mountains months after the Sept. 11 attacks on the United States.

A spokesman said the new operation also would prepare the way for reconstruction in impoverished provinces along the Pakistani border — a reward the military hopes will loosen villagers’ tongues.

“It’s certainly about more than one person,” Lt. Col. Bryan Hilferty said. “We do have confidence, though, and the leaders of al-Qaida and the leader of the Taliban need to be brought to justice — and they will be.”

Afghan officials hailed the new push and said their forces were fully involved.

“They are trying to eliminate the enemies of Afghanistan and the enemies of the world,” said Hilalludin Hilal, the deputy interior minister in Kabul.

American commanders have vowed to crush militants and snare bin Laden as well as Taliban leader Mullah Mohammed Omar this year, with a combination of military might and desperately needed aid.

But they face enemies — estimated at less than 1,000 active fighters by a top U.S. general this week — that present no easy target, moving in small groups and preying on civilians, including aid workers and government officials, as well as military targets.

Hilferty said the new operation, which began early today, would continue tactics already employed by the 13,500 U.S.-led troops tracking militants more than two years after the fall of the Taliban.

That includes frontier patrols, house-by-house searches and surprise checkpoints and air assaults.