Even as the U.S. geared up for a war in Afghanistan, another military force claimed a victory against the Taliban in heavy fighting Sunday.

The Northern Alliance, a loose confederation of Afghan opposition groups, announced it captured a key district of Balkh province and killed at least 80 Taliban militia fighters. Gen. Abdul Rasheed Dostum, chief of the Jumbish-e-Milli opposition group, said in a telephone interview that at least 200 Taliban fighters were captured and that his side had two men injured.

A Taliban official in Kabul confirmed the fighting but insisted the opposition alliance had made no gains in the region, 185 miles northwest of the Afghan capital. The official spoke on condition of anonymity.

But it was not possible to independently confirm the claims of either side. All of Afghanistan's neighbors have closed their borders at the request of the United States and nearly all foreign officials, including U.N. and international aid workers, have left the country.

Many see war with the mountainous central Asian country as increasingly likely as the Bush administration with increasing certainty points the finger at Saudi millionaire Usama bin Laden as the mastermind behind the Sept. 11 suicide attacks on the World Trade Center and the Pentagon . At last count, well over 6,000 were dead or missing.

President Bush  has demanded the Taliban hand over bin Laden -- who has lived in Afghanistan since 1996 -- and his lieutenants and close down his training camps, or face American military action.

In the latest military ramp-up, U.S. Air Force sent B-52 bombers capable of dropping or firing long-range cruise missiles and an array of other weapons to an undisclosed location after leaving overnight from Barksdale Air Force Base in Louisiana. The Defense Department on Saturday also called up another 5,172 National Guard and reserve troops, raising to 10,303 the total of Air National Guard Air Force Reserve troops called to active duty since Thursday.

The Taliban rejected the demand and warned Afghans to prepare for a holy war to defend the country.

Taliban forces have been reinforcing their positions along the long, porous border with Pakistan, prompting similar moves by the Pakistani military. A column of about seven tanks loaded on flatbed trucks could be seen Sunday moving toward the border from the northwestern Pakistani city Peshawar, according to witnesses.

Since the Sept. 11 attacks and U.S. threats of retaliation, thousands of Afghans are believed on the move, seeking shelter outside cities. Pakistan, Tajikistan and Iran have closed their borders with Afghanistan, leaving tens of thousands of destitute Afghans stranded on their side of the frontier, many without enough food.

Because so many people have left Kabul, Taliban police have stepped up security patrols in the streets to prevent looting of abandoned houses. Taliban police arrested five people Sunday for carrying weapons, according to Ahmedullah Ahmedi, the police chief.

The closing of Afghanistan's borders also has cut off food and medicine imports, leaving many shops, markets and hospitals with shortages.

The Associated Press contributed to this report