British police are investigating after a "number of people" are believed to have been attacked with pepper spray by a group of men who then fled.
Police were called at 8:11 a.m. to a multi-storey car park in Terminal 3 after reports of an assault on several people, the Telegraph reports.
A statement from police said: "A number of people were sprayed, with what is believed to be a form of pepper spray by a group of men who then fled the scene."
Armed police attended and a man was arrested on suspicion of assault. He remains in custody and enquiries are ongoing to find other suspects. Police are not treating the incident as terrorism.
There are currently some traffic disruptions in the area and Terminal 3 remains open. Commander Peter Stevens said: "At this stage, we believe the incident involved a group of people known to each other, with an argument escalating and resulting in a number of people being injured. Our officers responded quickly and there will be an increased police presence at Heathrow Airport throughout the morning, to continue the investigation and ensure the safety of those in the area. We are not treating this incident as terrorism. I understand the concerns of the public and would like to thank those in the area for their cooperation this morning."
Heathrow Airport is advising passengers to allow extra time when travelling to the airport, and to check with their airline with any queries.
There were disruptions to train and tube services, with some delays on the Elizabeth line and Piccadilly line.
National Rail said on its website that lines had reopened, allowing trains to stop at Heathrow "after emergency services dealt with an incident at the airport".
