A British Airways plane made an emergency landing at London's Heathrow airport on Friday after a "technical fault", forcing officials to close both runways.
Emergency slides were used to evacuate the plane's 75 passengers while amateur footage shot near the flight path showed smoke spewing from the Airbus A319's right engine shortly after takeoff.
The northern runway at Heathrow - one of the world's busiest airports - remained closed following the incident at around 9:00am (8:00am), a Heathrow spokesperson said, but the southern runway was later reopened.
"BA762 Heathrow to Oslo service returned back to Heathrow shortly after takeoff due to a technical fault," a British Airways spokesman said.
"The aircraft landed safely and emergency slides were deployed."
The spokesman declined to comment on speculation that the plane's engine had failed.
"Emergency services attended the aircraft and we will be carrying out a full investigation into the incident."
The spokesman also stressed that there was "absolutely no indication" that the incident was terror-related.
"This is a purely technical issue," he said.
London Fire Brigade said a crew had assisted the airport's fire service with "an aircraft fire".
"We believe the fire is now out," it added.Airport officials briefly closed both runways at Europe's busiest airport, causing delays. They later resumed operation, but passengers were advised to check their flight status.