LONDON, July 4 (Xinhua) -- Two fire alarms within minutes Tuesday have caused London's Heathrow Airport and Euston Station evacuated.
Although thousands of people were ushered out of both the station and Heathrow's Terminal 3, there were no reports of any injuries or casualties.
As the fire alarms rang out, station staff led crowds of people to areas outside the terminal.
Both Northern and Victoria London Underground lines were disrupted due to the closure as British Transport Police (BTP) officers headed to Euston, which links London to the north of England and West Scotland..
A spokesman for British Transport Police said: "Euston has been evacuated due to a fire alarm activation. Units of the BTP are on the scene."
Transport for London later confirmed the alert was a false alarm and the station reopened shortly after 1:30 p.m.
One train traveller, Matt Haig, said on social media: "Just been evacuated from Euston underground. The collective panic was a bit intense."
London Heathrow Airport's Terminal 3 was also evacuated Tuesday when fire alarms sounded. Passengers were told to leave the building shortly before 1 p.m. as alarms rang out throughout the terminal.
Emergency vehicles raced to the terminal, but it was found to have been a false fire alarm.
One passenger described how armed police were on duty during the alert with only security personnel allowed to enter the building.
An airport spokesman said Terminal 3 was evacuated following a fire alarm, adding: "Our teams have investigated and there is no fire in Terminal 3 despite the alarm. We are investigating this as a matter of urgency."
Passengers were allowed to return to the terminal once the all-clear was given.
