A major security incident unfolded at Heathrow Airport near London on Monday. Police arrested at least one person, and Terminal 3, one of the UK's busiest airport terminals, was completely closed to passengers.
Sky News reported that the incident began in the Terminal 3 parking area and that at least two suspects fled the scene. Social media users said they experienced breathing difficulties after being exposed to a chemical substance.
Footage circulated online showed officers restraining a man outside the terminal building at the UK's largest airport. Police blocked roads leading to the airport and deployed large forces to the area.
London police said the incident was not a terrorist attack but a fight between two groups of passengers, during which both sides sprayed each other with pepper spray or tear gas, and passersby were affected after inhaling the substance.
