The United States rushed reinforcements to try to wipe out Al Qaeda forces battling in the eastern Afghan mountains Thursday as allied airstrikes intensified.

"We're continuing to bolster our efforts, and units are continuing to maneuver in fire today, clearing ridgelines, caves and pockets of Al Qaeda resistance," Maj. Bryan Hilfery said.

A spokesman for the 10th Mountain Division, Hilfery said ground fighting continued Thursday but he had no word on new casualties. He said U.S.-led forces had killed 100 Al Qaeda and Taliban fighters on Wednesday alone.

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U.S.-led infantry units have cleared out several cave hideouts and Al Qaeda compounds, including some where troops found AK-47 ammunition, medicine, night-vision devices, and documents, including a Saudi identification card.

Eight American and three Afghan troops have died since Operation Anaconda began March 1.

In Kabul, five international peacekeepers two Germans and three Danes were killed while trying to defuse a Soviet-era missile.

Eight peacekeepers were injured in the first fatal accident since the force, which is separate from the U.S. military operation, was deployed to Kabul in December.

Throughout the morning Thursday, thunderous blasts from U.S. B-52 bombers shook the mountains southwest of Gardez. Dozens of U.S. Army Apache attack, armed with 30 mm guns and Hellfire missiles, pounded targets in the narrow, craggy gorges.

The air bombardment, felt in Gardez, 30 miles from the targets, appeared heavier than in recent days as the United States accelerated efforts to crack the Al Qaeda resistance.

Throughout the night Wednesday, U.S. transport helicopters shuttled between Bagram air base north of Kabul and the battle from to the south, bringing in fresh supplies of food, fuel and ammunition.

In Washington, Gen. Tommy Franks, commander of U.S. forces in Afghanistan, said the number of Americans in the operation grew by 200 to 300 over the past two days, for a total of roughly 1,100. U.S. officials said they joined about 1,000 Afghan fighters and a small number of elite, special operations troops from six nations.

Afghan commander Ismail Khan, however, said, "There are 5,000 soldiers collecting in Shah-e-Kot for a final offensive on the Al Qaeda to finish them off."

Khan said a U.S. special operations unit moved into the battle area Wednesday.

"I think the days ahead are going to continue to be dangerous days for our forces," Franks said in Washington. "But the alternative to taking such a risk is not acceptable."

On Wednesday, Franks raised the possibility sending in even more firepower, including additional transport aircraft, infantry and special operations troops. He described the situation on the ground as "very messy," and increasingly dangerous.

Facing the allied soldiers is a force believed made up of Arab and other foreign fighters from Al Qaeda with some of their Afghan Taliban allies.

They are armed with mortars, small cannons, rocket-propelled grenades, shoulder-fired anti-aircraft missiles and Kalashnikov rifles.

U.S. estimates of enemy strength appeared to have been low going into the offensive. Initially, U.S. estimates put the size of the force at 150 to 200 fighters. Subsequently, U.S. officers revised those numbers to "the neighborhood of 600 to 700 enemy."

The commander of the operation, Maj. Gen. Frank L. Hagenbeck, said more Al Qaeda and Taliban fighters had infiltrated the 60-square-mile area battle zone to join the battle.

Earlier in the week, the Afghan Taliban commander in the hills, Saif Rahman, issued a call for jihad, or holy war, against coalition forces, saying it was the first responsibility of Muslims.

Franks said there was no sign of dug-in Al Qaeda and Taliban fighters trying to flee the region which commanders say they have encircled.

But as recently as Tuesday night, Taliban holdouts managed to bring the bodies of five slain fighters from Shah-e-Kot to the village of Surmad in the foothills for burial, said shopkeeper Abdullah Jan, who was in Surmad on Wednesday.

When asked how the Taliban could sneak by the allied forces blocking the mountain paths, he said: "There are hundreds of smuggler routes," across the rugged terrain.

A local Afghan commander, who goes by the single name Isatullah, said U.S. forces received enemy estimates from an Afghan military leader from a different region who was unfamiliar with the territory.

Operation Anaconda is intended at crushing Al Qaeda fighters who came to this area after the collapse of Taliban rule last year.

Afghans say neither the former Taliban supreme leader Mullah Mohammed Omar nor Al Qaeda chief Usama bin Laden is believed to be in the Shah-e-Kot area.

The Associated Press contributed to this report.