The train station in the heart of London announced the closure just at 11.20am on Thursday ahead of the evening's rush hour.
Transport for London confirmed: “Euston Underground station is closed due to a person on the track. Trains are non-stopping - please use nearby stations."
It later confirmed that the station had reopened fully and "trains are now stopping as normal."
Information was written on a white board as commuters were rushed outside.
Emergency vehicles are standing by outside the rail station.
Customers have not been given any further details about the incident and the train station has yet to release any more information.
However, several police trucks are also stationed outside one of the capital’s busiest railway stations.
Flynetpictures.co.uk
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⚠ Some train services may be held for short periods while we investigate a customer incident at Euston station. Updates to follow
— Victoria line (@victorialine) February 1, 2018
Photographs showed that there were fire engines on the scene.
A spokesman for the Victoria line warned that "some train services would be held for a short period of time" while the incident was probed further.
Commuters have taken to Twitter to suggest that the incident might relate to a person on the railways tracks. But this has not been confirmed by the station.
One worried commuter took to Twitter to ask: “What’s going on at Euston station?”
Another tweeted: “Something heavy going on at Euston station here!!”
Flynet pictures
The message on the white board said: “Due to a serious customer incident, Euston station is closed for the foreseeable future.”
Station managers can be seen talking with the police as commuters mill around trying to find out more information.
A spokesman for Euston station told Express.co.uk: “We have checked with operations at the station and they said everything is operating normally.
“We have seen the pictures of the police trucks stationed outside and we have been told that nothing untoward is taking place at Euston Station.”