GLASGOW, Scotland—British police searched houses near Glasgow, Scotland's biggest city, on Sunday after what they said was a terrorist attack on its airport linked to two failed car bombings in London.
Britain raised its security level to "critical" — meaning the risk of another attack was imminent — following the airport incident, in which a fuel-filled, four-wheel-drive slammed into the entrance of the terminal and burst into flames.
"We are dealing with a long-term threat. It is not going to go away in the next few weeks or months," Prime Minister Gordon Brown, himself a Scot who took office only last Wednesday, said in a sombre appraisal of the terrorist threat facing Britain.
Two men, one badly burned and in critical condition, were arrested after Saturday's attack, which took place on one of the busiest days for Scotland's main international airport.
Two more people were arrested later in northern England. Five members of the public were slightly injured at the airport.
Wearing white plastic bodysuits and face masks, police in Glasgow combed several houses near the airport, in the town of Houston, about six miles (10 km) west of the city.
Neighbours said two Asian men had moved into one of the searched houses, a five minute drive from the airport, about a month ago but had kept very much to themselves.
"I don't remember seeing them at all," said Mae Gordon, 67.
"They were the only people around here you would never see."
Britain has seen an increase in terrorism-related attacks since the Sept 11 strikes on the United States and since it joined U.S. forces in invading Iraq in 2003. Some analysts believe the latest attacks may be designed to exert pressure on Britain to withdraw its troops from Iraq and Afghanistan.
Brown, who took over from Tony Blair on Wednesday, convened a meeting of Britain's top security chiefs to discuss measures to handle the first big test of his leadership. In a short address, he urged the nation to be vigilant.
Appearing on BBC television on Sunday, Brown warned the fight against terrorism would be drawn out.
"Irrespective of Iraq, irrespective of Afghanistan, irrespective of what is happening in different parts of the world, we have an international organisation trying to inflict the maximum damage on civilian life in pursuit of a terrorist cause that is totally unacceptable to most people," he said.
Jeep Ablaze
In Glasgow, 400 miles (600km) north of London, the green Jeep Cherokee, heavily laden with fuel, was driven at speed into the glass front doors of the airport terminal before being engulfed in flames.
The attack came barely 36 hours after police thwarted a possible al Qaeda plot in London in which two cars loaded with fuel, gas canisters and nails were left in the centre of the capital ready to detonate.
"I can confirm that we believe the incident at Glasgow airport is linked to the events in London yesterday," the top police officer in the Glasgow area, Willie Rae, told reporters.
"There are clearly similarities and we can confirm that this is being treated as a terrorist incident."
The series of plots come almost two years since the July 7, 2005 attacks on London's transport system, when four British Islamists blew themselves up and killed 52 commuters.
The London car bombs also appeared to mirror an earlier plan, uncovered in 2004, in which an al Qaeda operative wanted to detonated gas-filled limousines in London, and another plan in which militants intended to attack a major night club.
In Glasgow, witnesses described those arrested as Asian men.
In London, police scoured hours of CCTV footage and extra squads were deployed on the streets after the discovery in the early hours of Friday of the vehicle packed with up to 60 litres of fuel, several gas canisters and a large quantity of nails.
A second Mercedes packed with gas and nails was later found to have been parked just a few hundred yards from the first.
British Muslim groups condemned the series of incidents and urged Muslims to cooperate with the authorities.
"We are utterly appalled by this sinister plot and comment the professionalism of the security services in aborting it," the British Muslim Initiative said in a statement.
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