British police have increased their patrols in downtown London where two cars loaded with potentially explosive materials were found Friday.
Investigators also reviewed video from security cameras to see if they can find who drove and then abandoned the two Mercedes sedans. The cars were filled with nails and canisters of gasoline and propane.
Government officials have been holding emergency meetings to figure out how to deal with the situation.
The head of London's anti-terrorism police, Peter Clarke, said the first car bomb was found outside a crowded night club, where a blast could have resulted in many fatalities and injuries.
A second car parked illegally in the area was towed to an impound lot near Hyde Park, where police discovered it also contained fuel canisters and nails. Clarke said the two incidents are clearly linked.
Next week, Britain marks the second anniversary of the July 7 London transit bombings, in which four Muslim suicide bombers set off explosions that killed 52 bus and subway passengers.
Some information for this report was provided by AFP, AP and Reuters.