British Authorities Foil Terror Plot to Blow up U.S.-Bound Aircraft

London (AP) - Britain's busy Heathrow Airport has become a traveler's nightmare amid a security crackdown prompted by announcement of a foiled terrorist plot.

British officials say police have arrested a number of people in a plot to blow-up U.S.-bound flights with explosives smuggled aboard in carry-on luggage.

Britain has raised its national threat level to "critical." that's the highest.

In the U.S., Homeland Security Chief Michael Chertoff is raising the alert level for flights coming into the U.S. from Britain to the highest level, code red. And he's boosting the alert level for all other flights to orange, the next highest.

President Bush has been briefed on the situation by Britain's Prime Minister Tony Blair.

Heathrow has been closed to most European flights. For outgoing flights, British Airways is banning carry-on bags, along with just about anything except for passports and eyeglasses.