LONDON -- A power outage struck the London Underground, causing widespread travel disruptions across the capital on Monday afternoon, Transport for London (TfL) confirmed.

Transport for London (TfL) said the issues had been caused by a short power outage which happened at about 2:30 pm (1330 GMT). Power has since been restored, but delays and suspensions in major lines are ongoing.

Claire Mann, TfL's chief operating officer, said: "Due to a brief interruption of the power supply to our network, several lines lost power for a short period earlier this afternoon.

"We apologise to customers whose journeys will have been affected. We are working to get the whole network up and running again as quickly as possible," Mann said.

It's believed a cable fault caused a small fire, which was brought under control by firefighters.

"The fault was resolved within seconds and did not interrupt supply from our network, but a consequent voltage dip may have briefly affected power supplies on the low voltage distribution network in the area," said a spokesperson for the National Grid.

Local media showed pictures of chaos and disruptions on the London underground networks. One passenger said they were stuck on their train for "quite a long time" as the doors weren't opening due to a lack of power.

Queues of passengers, including tourists with huge suitcases, the elderly and disabled people, were seen making their way up broken-down escalators in some stations, as no lifts were working.

"We were told to immediately leave the station," said another passenger.

It remains unclear when the services will resume completely.