Oxford Circus Tube station has been evacuated following reports of an incident as videos emerge of panicked commuters and shoppers running from the scene.
Oxford Circus tube station was evacuated following a "customer incident".
Armed and unarmed officers are on scene and dealing along with colleagues from British Transport Police.
Video taken near the busy shopping street shows pedestrians running away from the scene.
"The station is currently closed, please avoid the area at this time," BTP said on Twitter.
The capital's transport operator, Transport for London, said trains were not stopping at the station due to the unspecified incident.
One Twitter user said: “London's #OxfordCircus being evacuated and armed police on the scene.”
Another added: “Too much police in Oxford Circus Street. People are screaming and running trying to escape the area. Everything was normal, changed in a min.”
It is not clear exactly what has caused the drama, with authorities saying it was a "customer incident".
Scotland Yard urged anyone on Oxford Street to "go into a building" and said "police have responded as if the incident is terrorist related."
However they said they had not yet found any suspects or any evidence of shots being fired at the station in Oxford Street - which has since reopened.
There is also no evidence of any serious casualties and police have now stood the incident down.
The MET Police released a statement saying: " Police have responded as if the incident is terrorist related. Armed and unarmed officers are on scene and dealing along with colleagues from British Transport Police.
"If you are on Oxford Street go into a building and stay inside until further direction.
Police received a number of reports of shots being fired on Oxford Street as well as the underground station.
Oxford Circus, Bond Street and Tottenham Court Road tube stations, which are all on the central line, are currently closed.
The London Fire Brigade are also on the scene with three fire engines and 15 firefighters are at the scene.
Witnesses reported being locked inside shops including Zara and Urban Outfitters as well as the famous department store Selfridges after emergency services were called to the scene shortly after 4.30pm.