Associated Press A thick black plume of smoke rises into the air above the Shah-e-Kot mountain range, some 30 kilometers (20 miles) away from the Paktia province village of Surmad, Afghanistan, yesterday. U.S. bombers blasted the cavernous mountains of eastern Afghanistan for a third day Sunday, pressing a new offensive against al-Qaida and Taliban fighters believed to be regrouping there.

SURMAD, Afghanistan - U.S. bombers pounded al-Qaida and Taliban positions in the eastern mountains of Afghanistan yesterday after a 1,500-strong coalition ground attack the day before failed to dislodge the well-armed renegades.

No major ground action was reported yesterday. However, U.S. Chinook helicopters ferried in supplies to American and other troops still in the hills, a local commander said, signaling preparations for a new round of ground fighting.

Afghan troops warned the operation to dislodge the regrouping Taliban and al-Qaida forces from their hide-outs in the mountain caves here in Paktia province was far from over.

"You can't do everything in one operation," said Raza Khan, an Afghan fighter recovering from Saturday's battle at the hospital in the provincial capital, Gardez. "This is Afghanistan. This is a guerrilla war."

Leaflets dropped by U.S. aircraft on the arid plains of the province urged residents to cooperate: "Hand over Taliban and al-Qaida or you will be destroyed. Come forward with information about Taliban and al-Qaida," read the leaflets, written in Afghanistan's two most common languages, Pashtu and Dari.

One American soldier and three Afghan fighters were killed Saturday on the first day of the ground operation, the Pentagon said. Six Americans were injured and airlifted out, a doctor at Gardez hospital said.

The assault, which began with bombing raids late Friday, was believed to be the largest joint U.S.-Afghan military operation of the 5-month-old terrorism war. Pro-U.S. Afghan troops approached the hideouts from three directions to isolate the renegades and prevent them from escaping.

Yesterday's operations were mostly limited to airstrikes as B-52s and other warplanes repeatedly pounded targets in the Shah-e-Kot mountains 20 miles east of Surmad and the Kharwar range to the west in Logar province.

The bombardments sent thick, black plumes of smoke above the snowcapped peaks and shook the ground in Surmad, where a constant stream of bombers streaked overhead.

However, one Afghan commander, Abdul Matin Hassan Kheil, said his men came under fire yesterday from mortars, heavy artillery and rockets fired from al-Qaida positions where Arabs, Chechens and Pakistanis were believed holed up.

"You can see it is a big operation," said Kheil, who led 50 fighters at a front-line position. He said coalition forces were dug in about one mile from al-Qaida bases in the Shah-e-Kot mountains.

At least three Chinook helicopters, which zoomed toward the mountains yesterday afternoon flanked by two jets, were supplying ammunition and food to American forces still in the hills, he said.

Kheil estimated it would take a month to push the renegades from their mountain strongholds.

Saturday's ground attack, carried out in snow-covered mountains ranging from 8,300 to 11,600 feet above sea level, appeared to have made little headway in dislodging Taliban and al-Qaida fighters who are regrouping in the hills of eastern Afghanistan.

"Firefights have been intense at times in heavy combat action," Maj. A.C. Roper, spokesman of the 101st Army division in southern Kandahar, told reporters yesterday.

A U.S.-led force of 1,500 Afghan allies, U.S. Special Forces and troops from the Army's 101st Airborne assault troops had assembled for the battle, a U.S. defense official said. Australian and Canadian troops also took part.

The Afghan allies made up the bulk of the force and approached the front from three different directions, some of them using pickup trucks rented for $200 from the Gardez bazaar, Afghans said.

About 600 fighters accompanied by at least 40 U.S. soldiers approached from Gardez, north of Surmad, said Safi Ullah, a member of the Gardez town council, or shura. Another 400 Afghans came in from Khost to the east, and an undisclosed number came from Paktika province to the south.

At least 70 vehicles carrying American and Afghan forces snaked around the back road behind Surmad to reach the front, said schoolteacher Rehmatullah, who uses only one name.

A Surmad village elder, who identified himself only as Mohammed, stroked his unkempt, red, henna-streaked beard and pointed toward a mountain beyond a stand of trees near the Shah-e-Kot range where the offensive was launched.

After the ground attack stalled, U.S. planes late Saturday dropped newly developed bombs designed to send suffocating blasts through cave complexes, military officials said. The "thermobaric" bombs were tested in December and officials said in January that they would be rushed to the region for the war.

Afghan fighters recovering yesterday at Gardez hospital described the operation as two-pronged, with one group of Afghan troops and U.S. Special Forces launching a frontal attack on the mountains and a second attempting to ambush from the rear.

Fighter Raza Khan said the American was killed when a pickup truck he was riding in was hit by a mortar shell.

Six injured Americans were airlifted out of the area by helicopter, said a doctor at Gardez hospital, Najibullah. Surmad residents said helicopters had gone into the mountains amid heavy firing Saturday.

The first stage of the offensive was designed to cut the road from Shah-e-Kot to trap al-Qaida and Taliban forces in the mountains, said Safi Ullah of Gardez. He said the plan also involved setting up checkpoints in the area to prevent them from escaping.

Pakistan closed its border to block fleeing al-Qaida or Taliban members and deployed extra army units and members of the Khasadar tribal militia to catch any who try to cross the frontier.

The rugged, caved mountains around Gardez have been a hiding place for Afghan warriors since anti-Soviet guerrillas used them as a base for their fight against Soviet troops in the 1980s.

Afghan officials say as many as 5,000 al-Qaida and Taliban fighters are regrouping in eastern Afghanistan and just over the border in Pakistan, urging the faithful to wage holy war against U.S. forces.

International aid workers and Afghan sources say al-Qaida and Taliban hiding in the Kharwar district targeted yesterday by airstrikes are being protected by the Taliban's former deputy foreign minister, Abdul Rehman Zahid.

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

But nearly two months ago, about 250 Taliban and al-Qaida soldiers told residents of Shah-e-Kot village, as well as 20 to 25 other villages tucked inside the mountains and foothills, to leave the area, said Haji Mohammed Gul, a resident of Murgurah-e-Khiel, near Surmad.

Initially, the villagers asked them to go away, he said. "But the Taliban and al-Qaida, with their Kalashnikovs, told them to leave."

Hundreds of families who were forced out of their homes now live in Surmad, said resident Gul Akhund, wrapped in a beige wool shawl against the chilly afternoon air.