(Scott Heppell ~ Associated Press)
Prime Minister Gordon Brown said, "It is clear that we are dealing, in general terms, with people who are associated with al-Qaida." He warned Britons that the threat would be "long-term and sustained" but said the country would not cowed by the plot targeting central London and Glasgow's airport.
"We will not yield, we will not be intimidated, and we will not allow anyone to undermine our British way of life," he said in a nationally televised interview.
A British government security official said a loose U.K.-wide network appeared to be behind the attacks but investigators were struggling to pin down suspects' identities -- even two arrested after they drove a Jeep Cherokee into Glasgow's main airport terminal Saturday and set it ablaze.
"These are not the type of people who always carry identity documents or who use their real identities," the official said on condition of anonymity because of the sensitivity of the inquiries. "Very little has been gleaned so far from the biological data."
(AP Photo/Scott Heppell)
Two men rammed the Jeep into the airport entrance, shattering the glass doors and igniting a raging fire. One of the suspects, his body in flames after the attack, was taken to the nearby Royal Alexandra Hospital, where police Sunday carried out a controlled explosion on a vehicle they said also could be linked to the plot.
On Friday, authorities thwarted coordinated bomb attacks in central London after an ambulance crew outside a nightclub spotted smoke coming from a Mercedes that turned out to be rigged with gasoline, gas canisters and nails. A second Mercedes filled with explosives was found hours later in an impound lot, where it was towed for parking illegally.
"We are learning a great deal about the people involved in the attacks here in Glasgow and in the attempted attacks in central London. The links between them are becoming ever clearer," Peter Clarke, head of Scotland Yard's counterterrorist unit, said in Scotland.
Heathrow Airport's terminal 3 was briefly closed Sunday night after a suspect package was found, but reopened once police confirmed the item was safe, authorities said.
Late Saturday, police arrested two people -- a 26-year-old man and a 27-year-old woman -- on a highway in Cheshire, northern England, London's Scotland Yard said. On Sunday, Staffordshire police said they also searched at least one home in nearby Newcastle-Under-Lyme.
And in Liverpool late Saturday, police arrested a 26-year-old man.