The station serves three Tube lines in the heart of the West End of London
Passengers have been evacuated from Oxford Circus Tube station in central London because of an emergency, British Transport Police has said.
Several police vans were parked at the corner of Oxford and Regent Streets.
Police said they would issue more details shortly but it is understood passenger alarms were deliberately activated on at least one train.
The matter is believed to be connected to a protest about the current political situation in Congo.
Oxford Circus serves the Bakerloo, Central and Victoria Lines.
It had been busy with Christmas shoppers throughout the evening, with retailers opening later, as is traditional on a Thursday.