London Mayor Ken Livingstone said late Thursday that there was no suggestion that the major power cut that hit the capital of Britain was a terror-related incident.

Thousands of tube travelers were stuck underground, and transport in London had been thrown into chaos after the power failure late Thursday hit central London and the southeast of England.

About 250,000 people were caught on underground, local reports quoted Livingstone as saying.

The mayor, who said Britain has never faced a crisis like this before, described the blackout as a "disgrace" and vowed to investigate the cause of the power cut. The blackout came two weeks after a massive blackout brought the northeast of America to its knees and prompted fears of a terrorist attack.

So far, there were no reports of accidents or injuries as a result of the power cut.

Network Rail spokesman Kevin Groves said services had been " badly" affected and the situation was "unprecedented" as far as he knew.

Some London Underground stations had been evacuated and 60 percent of services had been affected.

All mainline train stations in south London, including Victoria, London Bridge and Waterloo, had been affected with commuters being asked to leave buildings.

Above ground, street lights were off but the 270 traffic lights that failed in central London were back on.

According to reports, power supply was slowly coming back to a small selection of areas.