Biggest mobilisation since Gulf

"US readies for War" the headline in the Washington Post said yesterday as the US military machine began a mobilisation, not seen here since the Gulf War, and a radical rethink of military tactics.

Congress rushed through an emergency $40 billion appropriation, half of it for defence, as Secretary of Defence Mr Don Rumsfeld called up 50,000 reservists, and the President asked for the authority to call up as many as one million. Most of them will go on security duties and will provide technical and ground crew back-up to the air force.

Others will strengthen logistics, communications and medical teams. Twenty-six airbuses have been put on immediate "strip" alert, ready to scramble at 15 minutes' notice.

State authorities around New York and Washington DC have called up 10,000 members of the National Guard to assist in rescue work, clearing debris and securing areas.

At Fort Bragg, the largest US military base, home to 42,000 troops, at least 1,000 soldiers have been ordered to shift to a 24-hour duty cycle, meant to replicate the patterns of combat duty.

The US will launch sustained military strikes against those behind the terrorist attacks, a senior Pentagon official told journalists late on Thursday. In the most explicit description yet of the Bush administration's intentions, the Deputy Defence Secretary, Mr Paul Wolfowitz, said the military retaliation would continue until the roots of terrorism were destroyed.

"One has to say it's not just simply a matter of capturing people and holding them accountable, but removing the sanctuaries, removing the support systems, ending states who sponsor terrorism," he told a news conference in a Pentagon briefing room which still smelled of smoke and soot.

Other defence officials confirmed the administration is considering options that include the use of air, sea and land forces over a lengthy period. They said it was clear the administration would go well beyond the limited strikes of recent years against Iraq, Afghanistan and Sudan.

The fact that the US is seriously considering the use of ground troops, most likely helicopter-borne paratroops and special forces, to carry out rapid in-and-out raids against terrorist bases marks a significant change in military thinking.

In the past the US has minimised its potential casualties, fearful of a domestic backlash against returning body bags, by using missiles and bombing attacks. The mood here has changed. Politicians and military leaders believe the public will accept casualties and believe there may be no option as such groups are extremely mobile and difficult to hit from the air.

Mr Rumsfeld also noted that combat planes continue to fly over the New York-Washington corridor. He has not decided when those flights should stop. "And we do have interceptors on 15-minute alert across the country on some 26 bases," he told CNN.

A senior White House official, speaking on condition of anonymity, said Mr Bush was planning a sweeping campaign against terrorist groups that could last several years. The official seemed to be bracing the public for the likelihood that, although Mr Bush may not act quickly, he will act forcefully with a series of strikes.

The Navy has two aircraft carrier battle groups - each with 75 war planes aboard - in the vicinity of the Arabian Sea, said Admiral Vern Clark, chief of naval operations. That is twice the usual number for that part of the world. The USS Enterprise, which was due to return home after being relieved earlier this month by the USS Carl Vinson, has been ordered to remain in the area indefinitely.

Those battle groups normally include cruisers and submarines, which could be used to launch long-range cruise missile strikes, perhaps as part of a prelude to attacks by manned aircraft such as B-2 stealth bombers or B-1 Lancers.

The Washington Post revealed that the CIA has been authorised since 1998 to use covert means including lethal force to pre-empt and disrupt operations launched by the organisation of Osama bin Laden under an order signed by President Bill Clinton.

But the paper cites intelligence sources as saying the challenge has been to get "realtime" information about the terrorist leader who is constantly on the move. They say his training camps in Afghanistan and the Middle East are now almost empty and that Iraq's President Saddam Hussein has also moved machines and men from bases.

In Congress, where current spending of $10 billion a year on anti-terrorist measures is seen as inadequate, there was broad support for the beefing up of human intelligence assets, seen as key to pre-empting future attacks. Senator Bob Graham (Dem, Florida) said: "We have to re-emphasise the importance of getting a human being who can get inside those cells and learn what their intentions and capabilities are."

Late on Thursday, the Senate approved amendments to a Justice spending bill that will make it easier to wiretap computers and combat cyberterrorism.

Airport security is also being revamped with increased baggage inspections and investment in new x-ray machines. Remote check-in has been ended and there have been calls for the federal authorities to take over airport security from private operators.