A BRITISH warship passed through the Suez Canal yesterday as the preparations continued for a potential military response to the terrorists' attacks in New York and Washington.

HMS Cornwall, a type 22 frigate, was the first western warship to sail through the canal on its way to the Gulf since the attacks last week.

While her mission is to take part in long-planned exercises with Oman, Britain is preparing to join the US in an assault on Osama bin Laden's strongholds in Afghanistan.

Britain also has a naval task force of 26 ships, led by the aircraft carrier HMS Illustrious, in the Gulf area for the exercises.

Security was unusually stiff for a warship transiting the canal. Two Egyptian police boats were alongside the destroyer and on deck sailors scanned the banks of the canal with binoculars.

Gareth Bayley, a British Embassy spokesman, said Cornwall would take part in manoeuvres off the Omani coast code- named Swift Sword along with 12 other Royal Navy ships. ''It is a big operation,'' he said.

Meanwhile, the aircraft carrier USS Kitty Hawk and four other American warships put to sea from the Yokosuka Naval Base in Japan yesterday for an undisclosed destination, although there were reports that they were heading for the Indian Ocean.

The US Navy already has two carrier groups in the Gulf and the Arabian Sea, while a third, led by the USS Theodore Roosevelt, left her home port of Norfolk, Virginia, earlier this week bound for the Mediterranean. Each carrier has 75 aircraft aboard and is accompanied by other warships.

More than 100 US warplanes are currently flying out to the region in readiness for operations and Thomas White, US army secretary, has said the US was preparing for ''sustained land combat operations''. The Pentagon has revealed it is sending B-52 and B-1 bombers into the area, along with F-15 and F-16 fighters, adding to an already strong US military presence in the Gulf.

But the name Operation Infinite Justice has been dropped after Muslims complained it was insensitive, because in Islamic belief, only Islam can provide infinite justice.

In Afghanistan, Taliban troops were reported to have taken up positions on the border with Pakistan ready to strike back if Pakistan helps in any US strikes.

''They are in a warlike position. They have prepared themselves for full-scale war,'' said Mohammed Gul, a Pakistani border guard. ''They have deployed fresh troops in the mountain posts,'' he said.

Pakistan was said to have countered with a fresh deployment of Frontier Corps soldiers stationed on opposite peaks.

It was reported yesterday that special forces troops have already begun a secret mission to capture or kill bin Laden.

Senior US and Pakistani officials said special operations forces had begun moving into countries bordering Afghanistan, where the terrorist was in hiding, the newspaper USA Today said.

Teams of soldiers were expected to start entering Afghanistan's mountainous regions within days to try to locate bin Laden, who is believed to be hiding in caves or underground bunkers.

Military analysts said elite forces from Britain and the US were likely to play a crucial role in any attack on Afghanistan.

Experts believe commandos, including SAS troopers and the US Delta Force, are already on the ground preparing for an undercover operation to prise bin Laden from his hide-out.

The US Army Special Operations Command at Fort Bragg, North Carolina, said it had received a deployment order, but would not say where it was being sent.

Meanwhile, it emerged yesterday that if SAS troops are ordered into action, they will be deployed in old helicopters as their new ones are not due in service until 2003.

While the new Mark III Chinook offers a range of high-tech up-to-date equipment, the current fleet remains ''more than capable'' of fulfilling the needs of any special forces operation, an MoD spokeswoman said.

There were also reports the US had sent two Hercules transport planes to Uzbekistan. The giant aircraft are capable of transporting vast amounts of supplies and support systems, and play a vital part in any military build-up.

In another concentration of forces, staff have begun arriving in Cairo for the Bright Star manoeuvres that the US and other western countries conduct with Egypt's armed forces every two years. Bright Star is scheduled to begin next month.