U.S. hits Taliban frontlines

Witnesses said they could not see the exact targets but the bombs were hitting areas where there were known concentrations of Taliban troops as well as aircraft placements.

Western policy makers say the approach of winter adds a new sense of urgency to the military campaign to capture or kill bin Laden. In the United States, the deaths of two postal workers kept thoughts of anthrax and germ warfare uppermost in many minds.

Pakistan, meanwhile, kept its southwestern Chaman border crossing with Afghanistan closed and refused to bow to U.N. demands that it let through rising numbers of frightened Afghan civilians in search of refuge.

Northern Alliance forces have been saying for days that they are ready to advance on Taliban fighters guarding the approaches to Kabul and the northern town of Mazar-i-Sharif, a strategic crossroads on the supply route to the capital.

Northern Alliance warlord Abdul Rashid Dostum said that his forces were locked in fierce battles with fighters of the ruling Taliban in the north of the country. "Our forces launched an attack yesterday and the fighting has been fierce," Dostum said.

"They (the Taliban) left many dead on the battlefield," he said in a brief interview. The Northern Alliance, of which Dostum is a member, has been in a standoff to the south of the strategic city of Mazar-i-Sharif, a prize that was once the stronghold of the Uzbek warlord and which he is eager to recapture.

But with Muslim mujahideen fighters loyal to Saudi-born fugitive Osama bin Laden reported to be bolstering Taliban defences, there has been little sign of any movement on the ground. "Our efforts from the air clearly are to assist those forces on the ground in being able to occupy more ground," U.S. Defense Secretary Donald Rumsfeld said on Monday as dozens of attack jets launched a second day of raids in the two areas.

Opponents of the Afghan campaign warn that strikes against a Muslim country during the fasting month of Ramadan will go down badly in the Islamic world.

Rumsfeld told a news conference in Washington that the priority was to eliminate terrorist threats from the world. "We have great respect for the views and concerns of the many countries that are cooperating in this effort," he said, but he added:

"History is replete with instances where Muslim nations have fought among themselves or with other countries during various important holy days for their religion and it has not inhibited them historically."