Police officers stand guard behind a raised vehicle barrier outside Buckingham Palace, Central London Saturday

British authorities have raised the terror alert to critical after three attempted terrorist attacks in two days - one in Scotland on Saturday and two in London on Friday. VOA's Sonja Pace has details from the British capital.

The alert was raised Saturday after two men crashed a four-wheel drive vehicle into the terminal building at Glasgow airport in Scotland. The vehicle caught fire on impact. Two men in the car were subdued and arrested, one of them was taken to a local hospital with severe burns. Police also say they found what they describe as a suspicious item on the man, which was then removed to a safe place.

Chief Constable Willie Rae of the local police would provide no further details, but did say this was part of a series of attempted terrorist attacks.

"I can confirm that we believe the incident in Glasgow airport is linked to the events in London yesterday [Friday]. There are clearly similarities and we can confirm that this is being treated as a terrorist incident," said Rae.

Early Friday morning a Mercedes car laden with gas canisters, gasoline and nails was found abandoned near a nightclub in London's popular Haymarket district. Later another car, illegally parked in an underground garage was towed to an impound lot where police discovered similar explosive materials.

Terrorism experts say indications are the attempted bombings are the work of Islamic extremists either linked to or inspired by al Qaida.

British Prime Minister Gordon Brown has been meeting with members of his cabinet and security services.

"I want all the British people to be vigilant and I want them to support the police and all the authorities and difficult decisions they have to make. I know the British people will stand together united, resolute and strong," said Mr. Brown.

Mr. Brown has only been prime minister since Wednesday when he took over from Tony Blair.

This coming week Britain marks the second anniversary of the July 7 bombings, in which four Muslim suicide bombers set off explosions on London's transport system, killing 52 bus and subway passengers.