Police were called to reports of a minor explosion shortly after 7pm at Southgate Tube station in north London.
The Met tweeted: "Officers remain at #Southgate tube station. Enquires are ongoing to establish the cause of a reported minor explosion at 19:03 hours. We are not aware of any serious injury."
We remain at Southgate Tube station in London following a reported minor explosion. A small number of people have been treated at the scene by @Ldn_Ambulance.June 19, 2018
British Transport Police said a "small number" of people had been treated at the scene.
Officers remain at the scene and the station is closed, BTP said.
The Met said officers had been called to reports of an explosion and people running at the station.
The force added: "Enquires are ongoing to establish the cause of the reported explosion, which appears to have been minor.
"We are not aware of any serious injury."