Commandos 'set to target caves'

While B52 bombers pound Taliban lines north of Kabul for the third day, the Americans are sending in more specialised commandos to help the anti-Taliban forces, and to try to find the hideout of Osama bin Laden.

US intelligence claims it has now narrowed Bin Laden's whereabouts to a handful of mountain sites. US forces have the networks of caves and tunnels under 24-hour surveillance from the air and ground, say military sources.

Meanwhile, Bin laden has called for a "Jihad" to overthrow Pakistan's rulers, who he accused of "living under the Christian umbrella".

US Defence Secretary Donald Rumsfeld said the US forces are "working very diligently" to insert teams of special forces, advisers and communicators throughout Afghanistan. He admitted one attempt to land commandos failed because it encountered unexpectedly heavy Taliban fire from the ground. This is believed to have been one of the raids by US Rangers in the Kandahar region two weeks ago. Several raids have been cancelled because of bad weather. National Security Adviser Condoleezza Rice said operations would continue throughout Ramadan. She said: "We cannot afford to have a pause."

The Bush administration is now signalling that it is preparing to mount a much bigger and longer campaign against the Taliban and Bin Laden than first envisaged. At the opening of his latest Pentagon briefing, Mr Rumsfeld reminded the audience of the length of time it took America to develop its campaigns against the Japanese and Nazi Germany following the attack on Pearl Harbour. "We're now fighting a new kind of war," Mr Rumsfeld warned. "It's unlike any that America has ever fought before. But as I have said, one of those differences is not the possibility of instant victory or instant success."

He restated the "initial goals" of the US-led campaign as denying the Taliban the ability to sponsor terrorism, and "to acquire intelligence that would facilitate future operations against al Qaeda and Taliban forces".

Mr Rumsfeld later dropped a heavy hint that General Tommy Franks, the land commander of the US operations, is planning a more detailed and longterm campaign for the spring. Like Desert Storm it would involve at least two, and possibly three corps, a force of over a quarter of a million troops.

A crucial political part of the plan is to build up a "coalition of the willing" of forces from the region. This was one of the main aims of the recent visit by General Franks to Uzbekistan and Pakistan. According to military sources, General Franks has been talking of trying to put together a force of Turkish, Pakistani and even Egyptian troops.

Plans for the bigger ground and air war are being prepared at US Central Command in Tampa Florida. British military sources have hinted at a bigger involvement of UK forces in the spring. The carrier HMS Illustrious is to stay in the Arabian Sea until next spring, when she is likely to be replaced by the carrier HMS Ark Royal. The helicopter carrier HMS Ocean is now returning form exercise off Oman for maintenance, after which she is due to return to the Gulf region.