Commuters at Blackfriars station were evacuated on Wednesday evening (February 7) after reports a "suspect package" was found at the station.
Just after 6pm, people were evacuated from Blackfriars station and it was closed due to a security alert, Transport for London said.
Circle and District line trains did not stop at the station while police made sure the scene was safe.
A spokesman for Transport for London said on Twitter at 6.14pm: "Blackfriars station is closed while we respond to a security alert."
Photos from outside Blackfriars station show a large police presence, with a British Transport Police dog unit also at the scene.
Commuters were urged to avoid the station if possible and were told tickets would be accepted on local bus routes during the security alert.
One Twitter user said: "Blackfriars [is] shut due to a bomb scare/suspect package."
Chris Hobbs added: "While waiting at Blackfriars station the barriers suddenly stopped letting people in and out. People hurried out of the building. Communication to commuters not great."
Transport for London said the station reopened at around 6.30pm.
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