Three explosive devices were found at London’s Heathrow Airport on Tuesday — where none exploded but one caught fire, British authorities said.
Investigators said the first package was found at Compass Center on the grounds of Heathrow Airport. The second was found at an aviation building at City Airport in Newham and the third at London’s Waterloo rail station.
Scotland Yard said the devices were packed inside small bags that were placed in envelopes.
Counter-terrorism officials believe the three devices are related.
None of the packages exploded, but officials said one instead caught fire when it attempted to detonate.
“The package was opened by staff at the building, causing the device to initiate. This resulted in part of the package burning,” a police spokesman said.
No flights at Heathrow, one of the busiest airports in Europe, or City Airport were affected by the threats, officials said.
Investigators are reviewing surveillance video in the search for suspects.