COMPLETE COVERAGE | FRONT LINES | AMERICA AT HOME | INTERACTIVES »

Sadler: Advances on Tora Bora

Sadler

(CNN) -- Eastern Alliance forces claimed Monday to have made key gains against al Qaeda fighters positioned high in the rugged White Mountains near Afghanistan's border with Pakistan, an alliance field commander told CNN.

CNN's Brent Sadler is in the area, and he reports a strategy shift in the attacks.

SADLER: There has been a significant change in the battlefield scenario today. After more than a week of sustained bombing by United States warplanes, this day the attention has focused to action from tanks by the Eastern Alliance anti-Taliban forces, which are pouring fire into al Qaeda positions in those mountains just behind me.

MORE STORIES Alliance claims gains against al Qaeda

At the top of those mountains is Tora Bora, where it's thought that Osama bin Laden himself may be directing very fierce resistance by al Qaeda fighters, using the forest and caves as cover.

For two days, they've been firing mortar fire from those al Qaeda positions against anti-Taliban supply routes. But the emphasis changed today with the anti-Taliban tanks pouring their cannon shells into those positions.

One of the ground commanders for the Eastern Alliance said that in late afternoon, his men were able to take some important al Qaeda positions. He's claiming to have captured two command centers and four tunnel complexes. Whether or not this is true, we don't know; we haven't gotten any independent verification. But if that does turn out to be the case, that is a significant capture of al Qaeda positions.

At nightfall, we saw a return of U.S. airplanes firing at positions at those hills behind me, really trying to take out heavy weaponry that al Qaeda has been using in the last few days. For an hour or more, those bombers were coming in with big explosions on top of those hills and lower down.

We also saw heavy-caliber machine guns from the anti-Taliban forces shooting at positions, tracer fighter popping away at al Qaeda. But al Qaeda is still very much dug in there, and al Qaeda still very much a force to be reckoned with.