Several hundred U.S. Marines massed outside of Kandahar Monday, just hours after they were deployed by helicopters on the edge of the Taliban stronghold.

An American commander said the U.S. troops had seized a desert airstrip within striking distance of the city, but provided no further details.

The deployment of the first large U.S. ground expeditionary force comes a day after the Taliban's last northern garrison, Kunduz, fell to troops of the Northern Alliance, leaving Kandahar the last major Afghan city in Taliban hands.

Sending in the Marines marks a perilous new phase of a conflict that until now has been focused on U.S. airstrikes backing up the opposition Northern Alliance, plus limited ground missions by several hundred American special forces fanned out in small units across Afghanistan.

Kandahar, the Taliban's home base and spiritual center, has come under fierce bombardment since the conflict began Oct. 7, and the Taliban have vowed to fight to the death rather than abandon the city. In the last three weeks, they have lost their grip on three-quarters of Afghanistan, plus the capital, Kabul.

Most of the top Taliban leadership is believed to be holed up in and around the city, including the militia's supreme leader Mullah Mohammed Omar. Efforts by tribal leaders over the past 10 days to negotiate a handover of the city failed to yield results.

Abdul Jabbar, an anti-Taliban Afghan tribal official in Pakistan, said his colleagues in Kandahar confirmed that U.S. troops were on the ground there.

The Marines, numbering in the "low hundreds," were to be followed by several hundred more from Navy ships in the Arabian Sea, a U.S. official said in Washington, on condition of anonymity. As many as 1,000 troops could be on the ground there within days, the official said.

Northern Alliance Forces Capture Kunduz

The arrival of U.S. troops came as the Northern Alliance claimed to have seized Kunduz after a two-week siege.

The fall of Kunduz, which came two days before talks were to begin in Germany on forming a broad-based government, leaves the Islamic militia with only a small slice of Afghanistan still under its control, mostly around Kandahar.

Thousands of Taliban troops as well as Arab, Chechen, Pakistani and other foreign fighters linked to bin Laden had been holed up in Kunduz, which the alliance said fell almost without a fight.

Pro-Taliban fighters including foreigners fled Sunday toward the town of Chardara, to the west, with alliance troops in pursuit, alliance acting foreign minister, Abdullah, said by satellite telephone from the north of Afghanistan.

While some chose to make a run for it, thousands of others surrendered as Northern Alliance troops moved in. Under a pact negotiated earlier between the alliance and the Taliban, Afghan Taliban fighters were guaranteed safe passage out of the city but the foreigners were to be arrested pending investigation into possible ties to bin Laden.

The capture of Kunduz was reported hours after alliance troops gained a small foothold inside the besieged city, then overran a town on its eastern flank.

Near the town of Khanabad, about 10 miles east of Kunduz, alliance troops spread across ridgetops held by the Taliban a day earlier and fanned out across fields to check mud buildings for enemy fighters.

On Kunduz' eastern front, wind whipped up huge billows of dust as a long column of troops and tanks waited to move in — first allowing a long column of surrendering Taliban to pass by.

"Hurry, let's go!" their commander yelled. "Let's go! Let's go!" soldiers shouted back.

"I feel very happy," said a 16-year-old Northern Alliance fighter, Maraj Adin, who was from Kunduz and hadn't been home in four years.

The Associated Press contributed to this report