KABUL, Afghanistan - Hundreds of Afghan and American soldiers are engaged in a new hunt for Osama bin Laden and other terror suspects in a mountainous region bordering Pakistan, the Afghan military said Monday.

The 700 troops, including 100 American soldiers backed by U.S. helicopters, blocked off a potential escape route for militants who could be hiding on the Pakistani side of the frontier, Afghan military commander Zakim Khan said.

"We have reports that this was a route used by both Taliban and al-Qaida," Khan said. "I don't know how many came and went here, but now they have one option less."

Khan, the commander of the Afghan 822nd border battalion, said that caves in the region were used during the war against Soviet occupation in the 1980s.

"I'm very optimistic we'll find something because the main road is covered with Afghan checkpoints," he said.

The area is across from Pakistan's Waziristan tribal region, long considered a possible hide-out for bin Laden and al-Qaida No. 2, Ayman al-Zawahri.

U.S. military spokesman Lt. Col. Matthew Beevers would not comment on any operations, saying it could jeopardize their success.