Their lines, reinforced by thousands of Arab and Pakistani volunteers, are generally believed to be the strongest in Afghanistan.

That would then allow the new units, the commanders say, to attack an estimated 2,000 to 5,000 Arab and Pakistani volunteers believed to be positioned to the rear of Taliban lines.

Taliban holdouts in the north, mainly Pakistani volunteers, fell back to the northern city of Kunduz to make a stand.

The plain that separates them from Kabul is crisscrossed with trenches and defended by a large Taliban force buttressed by Al Qaeda and Pakistani volunteers.

Mr. Ibrahim said he was a commander of 2,000 Taliban forces and 200 Pakistani volunteers on the front line just north of Kabul in the fall of 2001.

The border is officially closed, but so porous that wounded Taliban fighters come across for treatment and Pakistani volunteers arrive in droves, ready to join them in war.

Al Qaeda instructors trained as many as 1,000 Arab and Pakistani volunteers at a time here.

In one, a Taliban-run basic training facility for Afghan and Pakistani volunteers, Mr. Haq was said to have been executed.

The Taliban militia makes open use of Pakistani volunteers, most of them students at religious schools who cross the border for a cause they consider holy.

At least 6 Taliban insurgents were killed by Pakistani tribal volunteers in Orakzai Agency.