A busy central London Tube station was evacuated on Wednesday due to a "casualty on the tracks", Transport for London (TfL) said.
The incident prompted the suspension of services between Seven Sisters and Victoria on the Victoria Line.
Several Twitter users said a person fell onto the tracks from a platform.
Among them was retired English cricketer and BBC Sport broadcaster Ebony Rainford-Brent, who tweeted: "I cannot believe what I have just witnessed. Absolutely horrific scenes at Oxford Circus and I just watched a man fall under the tube 2m in front of me. @TfL this is UNACCEPTABLE that in one of the most sophisticated cities in the world stations are allowed to get this RAMMED."
Details of the incident had not been confirmed by authorities at the time of writing.
This footage shows police and medical workers entering the station after its evacuation and closure.