Updated

The Afghan opposition launched an assault on the ruling Taliban militia from an air force base just north of the capital, in an attack coordinated with Sunday's U.S.-led military action against Afghanistan.

Northern alliance forces that control the Bagram air force base fired multiple-rocket launchers at Taliban forces that control the surrounding mountains. The Taliban returned fire using Soviet-made BM-21 rockets.

The base is about 25 miles north of the capital, Kabul, and the opposition has suggested it could eventually be used as a base for U.S. forces. The Taliban still dominates the high mountains around the base.

The opposition forces attacked Taliban positions at around 10 p.m., about an hour after the U.S. led strikes against Afghanistan began.

Meanwhile, in neighboring Tajikistan, an opposition spokesman said the alliance knew that the United States intended to attack military targets in both the Afghan capital Kabul and the city of Kandahar.

Asked about the immediate plans of the northern alliance, Afghan embassy official Rahimullah -- who like many Afghans uses one name -- said that the opposition could make an attempt to enter Kabul.

"The northern alliance is north of Kabul and will be involved in the fighting," Rahimullah told the Associated Press during an interview in front of the Afghan Embassy in Dushanbe, the Tajik capital.

When asked to be more specific, Rahimullah said: "Maybe two days, maybe a week. It's a military operation, so I can't specify."

He predicted that the fighters could make substantial advances in coordination with the air attacks. "We have a united front," he said.

The northern alliance uses Tajikistan, which shares a border with Afghanistan, as a diplomatic base. Supplies also flow to the alliance by way of the country.

Russian forces guard the Afghan-Tajik border, and Russia is sending military assistance to the anti-Taliban forces.

Before the strikes, the Taliban said they had sent thousands of troops to the border with Uzbekistan, whose president has allowed U.S. troops use of an air base for the anti-terrorism campaign.

The Taliban claims could not be independently verified. However, Russia's Interfax news agency reported Saturday that Taliban troops had been moving long-range artillery and multiple rocket launchers toward the border. More than 10 guns and rocket launchers had moved within range of the Uzbek border town of Termez, Interfax said, quoting Afghan opposition sources.

The Taliban are estimated to have some 40,000 fighters -- around a quarter of them from Osama bin Laden's organization.