A suspected CS gas attack has occurred on a London Underground train.
It happened at 09:13 BST on board a Tube train at Oxford Circus in central London.
British Transport Police said a number of people were treated at the scene by paramedics for coughing and lack of breath – but there were “no further concerns for their health”.
The force has appealed for witnesses and released CCTV images of two people they want to speak to.
A Transport for London spokeswoman said the train had been taken out of service and to a depot for quarantine.
Oxford Circus, situated on the junction of Oxford Street and Regent Street, serves the Central, Victoria and Bakerloo lines.
CS gas, also known as tear gas, can cause a burning sensation around the eyes and difficulty in breathing.