JABAL SARAJ, Afghanistan -- The Taliban acknowledged early Saturday that it lost the city of Mazar-e-Sharif to opposition forces in northern Afghanistan. American officials confirmed opposition forces were in the city and said fighters of the ruling Islamic militia were fleeing.
The Taliban's Bakhtar News Agency said fighters of the Islamic militia had been forced to retreat with their weapons and equipment because of sustained bombing by U.S. warplanes.
"For seven days continuously they have been bombing Taliban positions. They used very large bombs," said Bakhtar chief Abdul Henan Hemat.
The capture of Mazar-e-Sharif on Friday was the biggest success since President Bush launched airstrikes Oct. 7 to punish the Taliban for refusing to hand over Osama bin Laden, chief suspect in the Sept. 11 terrorist attacks on the United States.
If the opposition can hold the city -- which in the late 1990s changed hands several times and was the site of bloody massacres -- it would open a land bridge to neighboring Uzbekistan, allow a flood of weapons and supplies to the opposition alliance and give U.S.-led forces their first major staging ground in Afghanistan for the campaign against the Taliban.
In Washington, Secretary of State Colin Powell said he couldn't confirm the fall of the city. But other U.S. officials, speaking on the condition of anonymity, said it was clear that the opposition had entered Mazar-e-Sharif and that at least some Taliban troops were on the run.
A senior defense official in Washington said reports from the area indicated that the anti-Taliban forces have taken the entire city and that large numbers of Taliban fighters have switched sides. But he stressed that the U.S. military had not been able to confirm those reports.
He added that the city could change hands again if, for example, Taliban forces found reinforcements for a counterattack.
The commander of the USS Theodore Roosevelt said scores planes from the aircraft carrier took off late Friday to attack Taliban troops retreating from Mazar-e-Sharif.
"We thought this would be a very slow advance on the city, (but) it appears the Taliban have fallen back and over the course of the day, we've seen numerous convoys coming out of that area," Rear Adm. Mark Fitzgerald said.
Alliance envoy Haron Amin said in Washington that alliance generals had "confirmed the liberation of Mazar-e-Sharif."
He said forces under three commanders occupied strategic high points near the city and the Taliban fled to the east and west of the city, many in pickup trucks and sport-utility vehicles.
"They are going to be in our territory," he said. "We will be able to cut them off."
A spokesman for one of those commanders, Gen. Rashid Dostum, claimed American Green Berets took part in the battle. But a senior defense official in Washington said he couldn't confirm the claim.
Philip Smith, Dostum's Washington representative, said the U.S. special forces along with CIA operatives and Turkish troops were also working with Dostum, a Uzbek commander who once controlled Mazar-e-Sharif.
Smith, who said he was in touch with Dostum via satellite phone, said the battle involved nearly simultaneous assaults on two fronts, which crumbled the Taliban lines.
Dostum claimed 1,500 Taliban soldiers were captured and many of them volunteered to fight for the alliance, Smith said.
Earlier opposition reports said about 3,000 Taliban fighters had been in the city, and claimed 500 of them died and 500 were captured.
In London, British Prime Minister Tony Blair said there had been "substantial progress" at Mazar-e-Sharif and there was no doubt "that the military momentum is now moving against the Taliban."
Vice President Dick Cheney said the city's loss would be a serious blow to the Taliban because they had worked so hard to protect it since the bombing began.
"It's a significant development," Cheney said in a telephone interview with The Sun newspaper of London. "It would be perceived, I think, as a significant defeat."
Mazar-e-Sharif has a population of about 200,000 -- most are ethnic Uzbeks and Tajiks, the same as the opposition. Most Taliban are Pashtuns, the largest ethnic group in Afghanistan.
In other developments:
-- Islamic fundamentalists in Pakistan burned tires, blocked transit routes and clashed with police in a nationwide strike Friday to protest their government's pro-U.S. policies on Afghanistan. Four demonstrators were killed.
-- Bush said the worldwide coalition against terrorism has never been stronger and added, "now is the time for action" on military, diplomatic and other fronts.
-- Britain plans to release a dossier of evidence against bin Laden next week, a senior official said Friday. British officials have expressed concern that public support for the U.S.-led military campaign in Afghanistan has wavered.
Mazar-e-Sharif has a large airport that could be refurbished for American and allied aircraft to conduct humanitarian missions and mount attacks against the Taliban. And the city controls a supply route from Uzbekistan, 45 miles to north -- a passage that does not get blocked by winter snowfalls, a key concern for the opposition alliance.
Losing Mazar-e-Sharif would also isolate Taliban units in northwestern Afghanistan.
An opposition spokesman, Ashraf Nadeem, said northern alliance fighters overran Mazar-e-Sharif's airport and then entered the city through Taliban lines at the Pul-e-Imam Bukhri bridge on its southern edge. Taliban forces appeared to have abandoned Mazar-e-Sharif in the face of the assault, he said.
"The whole city is now under control of our forces," Abdullah, foreign minister of the Afghan government-in-exile, reached by telephone from Jabal Saraj.
"The air support from the United States helped our forces make their advance," said Abdullah, who uses only one name. Reporters have no access to the area around Mazar-e-Sharif, and telephone links to the city have been cut.
The opposition announced an amnesty for anyone who formerly supported the Taliban, Nadeem said by telephone from Dar-e-Suf. The opposition directed the drive on Mazar-e-Sharif from Dar-e-Suf, about 50 miles to the south.
Human rights groups say the opposition put as many as 2,000 Taliban to death in Mazar-e-Sharif when they took the city back from the Islamic militia in 1997.
In 1998, when the Taliban recaptured the city, they were accused by the same groups of massacring several hundred people, many of them Shiite Muslims.
Elsewhere, U.S. jets struck Taliban front line positions about 30 miles north of Kabul. The jets and B-52 bombers repeatedly hit Taliban targets overnight and early Friday north of Kabul and around Kandahar.
The opposition has said it intends to launch an offensive to take Kabul, but so far has not tried to move against the heavily entrenched Taliban lines there.
Powell told reporters it would be best if the opposition did not move immediately, since Kabul's population is likely to be hostile to it.