Navy SEAL Neil Roberts was captured and slain by a band of Al Qaeda fighters while helpless U.S. officials watched his killing on a live video broadcast from a surveillance plane.

The tragic incident that led to the American soldier's death began when U.S. troops in eastern Afghanistan poured from the belly of a Chinook helicopter on Monday -- and a rocket-propelled grenade fired by Al Qaeda hit the craft, but failed to explode.

The troops rushed back onto the chopper and took off -- but a head count showed one man was missing.

It was Roberts -- who fell out of the chopper's open rear door when the pilot turned the craft to get away.

Roberts, 32, survived the fall. His commanders, some thousands of miles away, witnessed his horrible fate on a live feed sent from a Predator drone plane overhead.

"We saw him on the Predator being dragged off by three Al Qaeda men," said Maj. Gen. Frank L. Hagenbeck.

Then Roberts was executed with a gunshot to his head.

Roberts, a petty officer 1st class from of Woodland, Calif., was based in Norfolk, Va., with a Navy SEAL unit.

A rescue team later recovered his body.

And Roberts' comrades-in-arms fought back yesterday, taking the battle to Taliban and Al Qaeda hideouts in the icy mountains near Gardez.

"We caught several hundred of them with RPGs [rocket-propelled grenades] and mortars heading toward the fight," said Hagenbeck. "We body-slammed them today, and killed hundreds of those guys."

The fighting, the war's bloodiest so far, came after a 24-hour pause that allowed U.S. B-52 and F-16 bombers to pound heavily guarded terrorist positions.

Then a U.S.-led force of 2,000 American, Afghan and allied troops resumed their perilous assault on the scorpion's nest of caves and mountain ridges in a 60-square-mile area in the Shah-e-Kot range.

The Arab, Chechen and Uzbek fighters and their families are holed up in the Al Qaeda stronghold in eastern Afghanistan.

They fought back with mortars, machine guns and rocket-propelled grenades as the ferocious battle entered its fifth day.

Eight U.S. troops have died in the battle, including one who died in ground fighting Saturday, and Roberts and six others who died in helicopter operations Monday.

U.S. and Afghan commanders said the Al Qaeda holdouts seemed to be running out of ammunition, weakening their resistance yesterday. Some seemed to scatter and burrow deeper into fortified cave complexes.

"They can't escape. They're surrounded. Slowly, slowly we are pushing in," Abdul Matin, an Afghan commander in the battle, said.

Pentagon officials said it is too early to say U.S. forces are gaining the upper hand, describing the operation, in frigid temperatures at altitudes as high as 12,000 feet against an enemy that is widely scattered, as one of the toughest and most complex of the war. Pentagon officials said the operation could take weeks.