Getting your Trinity Audio player ready...

One American was killed and a number wounded Saturday when U.S. and Afghan troops attacked suspected Taliban and Al Qaeda forces in the largest allied ground operation of the war in Afghanistan.

The Pentagon said the fighting, south of Gardez in the mountainous eastern province of Paktia, also took the lives of three Afghan fighters and wounded others.

U.S. Special Forces and Army 101st Airborne assault troops joined Afghan fighters and coalition forces in an assault that began early Saturday in Afghanistan, or 9 p.m. EST Friday, the Pentagon said.

U.S. bombers, carrier-based fighter jets and AC-130 gunships also hammered the area, and warplanes for the first time dropped new “thermobaric” bombs designed to send suffocating blasts through cave complexes, military officials said.

More American and coalition ground troops–including several hundred soldiers from the 101st, according to one report–were thrown into the offensive than in any other operation in Afghanistan, U.S. officials said. Previously, the largest ground operation was the December attack on the Tora Bora cave complex.

Although the Pentagon would not specify casualties among U.S. troops Saturday, at least 16 Americans reportedly were wounded in addition to the fatality.

A senior defense official said that the combined force of Afghan and American troops numbered more than 1,000 and that most of them were Afghan fighters, who wore pieces of white paper on the tops of their black hats to help helicopter pilots distinguish them from enemy fighters. Another source put the number of Afghans alone at 1,500.

The U.S. has 5,000 service members in Afghanistan, including about 2,000 troops of the 101st Airborne at Kandahar airport.

The objective of the assault, said the senior official, was not to counter a specific threat but to kill or capture Al Qaeda members, numbering in the low hundreds, who were regrouping in the area.

“We have said all along that we will continue to go after pockets of Al Qaeda when and where we find them,” said Pentagon spokeswoman Victoria Clarke.

Estimates of how many Al Qaeda and Taliban combatants are holed up in the mountains vary, but they range from dozens to thousands. Afghan fighters interviewed in Gardez, about 20 miles north of the battle, said the Americans told them there were about 4,000.

Despite the apparent intensity of the allied ground attack Saturday, Afghan officials said there had been little headway made against combatants who fought back with artillery, mortars and heavy machine guns. Afghan forces broke off the assault in the early afternoon and withdrew.

Orders from Gen. Tommy Franks, head of the U.S. Central Command in Tampa, set the operation in motion, officials said. President Bush was kept fully briefed Saturday, and Secretary of Defense Donald Rumsfeld monitored the operation from the Pentagon.

A Central Command statement said coalition forces had suffered casualties, but it provided no further details.

Four other members of the U.S. military have been killed in combat since the war began Oct. 7, three of them when bombs from a B-52 missed their target, and one who was killed in a battle near Gardez in early January. A CIA operative was killed during a Taliban-led prison uprising. Fourteen other service members have died in non-combat operations, many of them in helicopter crashes.

The Pentagon had signaled Friday that a major offensive was in the offing when officials said the Central Command had found pockets of Al Qaeda and Taliban fighters near Gardez.

Air Force Brig. Gen. John Rosa of the Joint Chiefs of Staff told reporters that Franks had only to give his approval for the assault against the pocket of suspected enemy fighters.

“We’ve been tracking this [regrouping] for several months,” Rosa said.

Remote, rugged and honeycombed with caves, the mountains around Gardez have been a hiding place for Afghan warriors since the mujahedeen used them as a base in their fight against Soviet troops in the 1980s.

Former Taliban front-line commander Saif Rahman was believed to be leading the Taliban and allied foreign forces still in hiding in the area.

Paktia was also a stronghold of Jalaluddin Haqqani, a U.S.-backed rebel commander in the 1980s who joined the Taliban and is sought by U.S. authorities.

Neither the former Taliban supreme leader Mullah Mohammed Omar nor Al Qaeda chief Osama bin Laden is believed to be in the area.

In Pakistan, a senior government official at the border town of Miran Shah said Saturday that troops have blocked all routes to prevent the escape of any Al Qaeda and Taliban members fleeing the attack.

The official, Javed Marwat, said a 60-mile strip bordering Afghanistan has been closed.

The last reported U.S. ground operation in Afghanistan was on Jan. 23, when at least 16 Afghans who were neither Taliban nor Al Qaeda members were killed, the Pentagon acknowledged last month.

Smaller, undisclosed raids have taken place since, said one U.S. defense official, speaking on condition of anonymity. Those raids have concentrated on gathering information about pockets of resistance, and they have at times netted documents or individuals who were interrogated and released, the official said.