GARDEZ, Afghanistan ? Allied Afghan commanders sent fresh troops Tuesday to bolster U.S.-led coalition forces battling al-Qaida and Taliban fighters. Pro-U.S. Afghans reported continued exchanges, although less intense than in recent days during which eight Americans were killed.

As coalition bombers blasted al-Qaida’s mountain strongholds, minesweepers led the way on the ground for allied troops to press on toward Shah-e-Kot, where hundreds of militant soldiers and their families are believed hunkered down, said fighter Nawab, who was at the front Tuesday morning.

Hundreds of U.S.-backed Afghan troops ringed the range in eastern Afghanistan’s Paktia mountains and the labyrinth of caves there to try to block the escape of any renegades.

“They can’t escape. They’re surrounded. Slowly, slowly we are pushing in,” front-line commander Abdul Matin Hasan Khiel said Tuesday.

The remains of seven American soldiers killed Monday when al-Qaida and Taliban fighters fired on U.S. helicopters were brought Tuesday to a base in Ramstein, Germany, heading for the United States. U.S. Army chaplains read psalms over the flag-drapped coffins. Another American was killed in a ground attack Saturday, the first U.S. casualty of the campaign.

The assault is the largest U.S.-led air and ground offensive of the Afghan war, designed to pound the renegade militants with waves and waves of airstrikes and squeeze them out of their hide-outs. Code-named Operation Anaconda after the snake that crushes its prey to death, it marks the first time U.S. conventional ground troops were used in an offensive operation.

Army Gen. Tommy Franks, commander of U.S. Central Command, estimated Monday that 100 to 200 enemy fighters had been killed in the operation and a small number taken prisoner. He said they included al-Qaida fighters, Taliban militia and Chechen and Uzbek fighters.

An Afghan commander on the ground at Gardez put the number of detainees at 60, all of them Chechens.

Franks said the offensive had as its objective a 60-square-mile area south of Gardez. Air support included A-10 ground attack planes, F-15 fighter jets, B-1 and B-52 bombers, AC-130 gunships, as well as some French jets Mirage 2000s and Super-Etendards.

The initial plan for the operation was for U.S. troops to take up blocking positions to prevent Taliban and al-Qaida from escaping, with Afghan forces leading the fighting, a U.S. defense official said Tuesday. He said he did not know how much the actual combat has strayed from the planning, but confirmed that Americans were blocking escape routes.

Afghan and U.S. officials said the Taliban and al-Qaida fighters were likely armed with shoulder-fired surface-to-air missiles such as Russian SA-7s and possibly American Stingers as well as mortars, grenades and canons.

Fighters returning from the front said clashes continued Tuesday although to a lesser degree than the fierce firefights of recent days.

“Last night and today, the firing was less,” said Nawab, who returned from the front-line at midday. “The first days there were lots of mortar and rockets. But last night and today it was less.”

He said about 50 U.S. Special Forces were fighting alongside Afghan soldiers about 2 1/2 miles from Shah-e-Kot.

About 60 Afghan fighters outfitted in U.S.-issued parkas, their heads wrapped in turbans, were heading to Shah-e-Kot on Tuesday from Jaji, northeast of the provincial capital, Gardez. Bright orange strips were affixed to the top of the transport trucks to identify them to the allied bombers and helicopters roaring overhead.

Other troops were apparently rotating out. About 30 trucks with Afghan soldiers and two four-wheel drive vehicles carrying coalition forces were seen heading to Gardez from Surmad, about 20 miles from the Shah-e-Kot mountains.

Franks said units of the 10th Mountain Division and the 101st Airborne Division had been sent into the battle area. Allied forces from a half-dozen other countries were also taking part, bringing the coalition numbers up to about 2,000.

The commander described the ground operation as a series of short, often intense clashes with small numbers of fugitives fought in bitter cold at elevations of 8,000 to 12,000 feet.

“We might find five enemy soldiers in one place and then perhaps some distance away from there we may find three and then some distance we may find 15 or 20,” Franks said. He described the battle area as “a very, very tough operating environment for our soldiers to be in.”

Roseuddin, an Afghan civilian who was in the village of Shah-e-Kot shortly before the attacks began, estimated the al-Qaida and Taliban force at about 600, commanded by a former Taliban officer, Saif Rahman.

Other Afghan civilians said as many as 2,000 Arabs, Chechens, Pakistanis and Afghan Taliban moved into the area after the fall of the Taliban stronghold of Kandahar on Dec. 7.

However, many of them had apparently slipped away, either to nearby Pakistan or other areas of Afghanistan’s mountainous east.

Neither the former Taliban supreme leader Mullah Mohammed Omar nor al-Qaida chief Osama bin Laden was believed to be in the area.

About 40 U.S. troops have been wounded, including 11 injured Monday, since the operation began Friday night in the snow-covered mountains southwest of Gardez.

Defense Secretary Donald H. Rumsfeld said half of the wounded were already back in the fight and the others were evacuated from the region.

Details on the two helicopter incidents were sketchy, but officials said the second helicopter was on a rescue mission.

A Central Command spokesman, Marine Maj. Ralph Mills, said an MH-47 Chinook helicopter was flying low on a reconnaissance mission when it was hit with a rocket-propelled grenade that knocked a soldier out of the aircraft and caused a hydraulic problem.

The helicopter landed about a half-mile away, Mills said.

A second MH-47 Chinook helicopter was flying in tandem with the first and rescued the downed crew, then returned to the area where the soldier fell out. The second helicopter dropped troops in that area, and six were killed in a firefight, Mills said.

The second helicopter returned and picked up the dead and wounded, he said. He said the wounded were being treated in a hospital in Afghanistan.

Several officials said the details of the battle may change as more information becomes available.

President Bush mourned the loss of the Americans, White House spokesman Ari Fleischer told reporters Monday afternoon as Bush flew to Minneapolis.

“The president has said to our country that we need to be prepared for casualties,” Fleischer said.