A man has been arrested after an alleged stabbing on board a Jubilee Line train at Green Park station during rush hour.
The central London station was closed following the reported attack and a victim was taken to hospital.
No officers were injured in the attack, British Transport Police said.
A video on social media shows a man in handcuffs surrounded by plain-clothed police being spoken to by an armed officer.
Supt Mark Lawrie said that a weapon was recovered at the scene and the station will be re-opened imminently.
A BTP Twitter account said that officers were called to reports of a stabbing on-board a Jubilee Line service.
They added: “Specialist officers have been deployed and the station remains closed while they attend. One person has been arrested in connection.”