Heathrow remains on terror alert

6.00pm

LONDON - Military presence at Heathrow airport has moved into a second day after security chiefs warned they had received information about a specific threat.

The decision to draft hundreds of troops into Heathrow came just hours before a fresh call for terrorist attacks on Western targets by al Qaeda chief Osama bin Laden.

A police source said on Tuesday (Wednesday NZT) the deployment was partly a precaution against a possible al Qaeda rocket attack on a plane.

When asked about the operation, Prime Minister Tony Blair's official spokesman declined comment on a rocket threat but said: "There is an ongoing operation in relation to a specific threat."

Police said the Heathrow measure was precautionary and designed to coincide with the end of the Eid al-Adha festival being celebrated by Muslims around the world this week.

The three-day Muslim celebration of the end of the annual Haj pilgrimage started on Tuesday.

A police spokesman said there was "increased policing" on the motorways surrounding Heathrow "to ensure that the airport area is secure".

There were reports of police stopping and searching cars on roads west of Heathrow that run beneath the airport's busy flight paths, citing powers under counter-terrorism laws.

ACTION "APPROPRIATE AND NECESSARY"

"Action would not have been taken of this nature unless it was thought to be appropriate and necessary," he added.

A police source said the operation was based on fears of a possible rocket attack, among other threats.

Last November, two missiles were fired at -- but missed -- an Israeli airliner as it took off from Mombassa, Kenya.

"From time to time, it is necessary to raise levels of security activity," the Metropolitan police said in a statement. "We think it is prudent to do so now."

"The current strengthening of security is precautionary and is related to action being taken in other countries and the possibility that the end of the religious festival of Eid may erroneously be used by al Qaeda and associated networks to mount attacks."

Troops were also called in to help guard other sites in London, in an operation that was connected to "a potential threat to the capital".

It was the first time the army has been posted at Heathrow since 1994, when the IRA launched a mortar attack on the airport.

Those passing through the airport on Tuesday morning welcomed the appearance of tanks and armoured cars on the approach to the passenger terminals.