US troops set for 'last' battle

The US is massing elements of two battalions of the 101st Airborne Division on the Afghanistan-Pakistan border for what is billed in Washington as "the last big fight" of the Afghan war.

The action is based on intelligence that Osama bin Laden and his top aide, Ayman Zawahiri, are in the tribal areas on the Pakistan side of the border, a Pentagon official said today.

The Washington Post says the US command has moved Apache helicopters to a special forces base near Khost, 20 miles from the Pakistan border. One senior officer said 1,000 infantry will eventually move into the area.

The plan is said to centre on fast-moving raids supported by air strikes to force al Qaeda fighters from their lairs in the wild landscape.

The raids are likely to be at night, when al Qaeda fighters tend to emerge from their hiding places. The al Qaeda will be tempted to counterattack, US officials say, exposing themselves to capture or death at the hands of US ground and air forces.

The aim is to keep them off balance, thwarting new attacks in Afghanistan or the United States. Conventional forces will operate only on the Afghan side of the border, Pentagon officials say. Special forces will work in Pakistan.

There have been two firefights this week in the area where US and Australian special forces killed four al Qaeda gunmen. The clashes took place a mile from the Pakistan border.