Two teenage boys have been stabbed in separate incidents at London Tube stations.
The victim was taken to hospital and treated after being stabbed in the back.
DI Nia Mellor, of the British Transport Police, said: “This was a violent assault committed during rush hour on the Tube network, causing great concern to members of the travelling public.
“Fortunately, the victim’s injuries are not life-threatening and he is in a stable condition.
"Officers will be at the scene today carrying our further enquiries and I ask any witnesses to please get in touch.”
A BTP spokesman added: "The victim, a teenage boy, suffered an injury to his shoulder and was taken to hospital for treatment."
The official Central Line Twitter account confirmed the station's closure, posting: "At the moment trains are not stopping at the station. This is while police respond to an incident.
"We’ll let you all know when the station re-opens and trains are stopping normally."
The zone 4 station was later re-opened.
Earlier on Monday afternoon, shortly before 4pm, officers from the Met police were called to reports of a stabbing at Upney Underground station in east London after a fight broke out.
The station was closed while emergency services attended the victim.
Barking and Dagenham police said: "Police called to Upney Underground Station at 15.46hrs today - two teenage boys were found injured. Both taken to hospital & one is being treated for stab injuries.
"We await an update on their condition.
"There have been no arrests. A crime scene is in place. Enquiries continue."
BTP were not investigating the Upney incident because it was not inside the Tube station.