British police have arrested three passengers aboard a plane at Heathrow airport in London. They were on Emirates flight EK004 to Dubai.
Metropolitan Police said they were taken into custody after verbal threats were made before the take-off.
The airport and terminal remain open, and an airport spokesman said other flights were not affected.
Witnesses told Sky News that armed police boarded the plane, which was due to take off around 2000 GMT on Friday, and took three young Englishmen away.
Police sources said searches had not found any threat to the flight, indicating that the incident could have been an ill-judged prank.
The BBC says it comes amid heightened tension at airports across the world following an unsuccessful attempt to bomb a plane flying from Amsterdam to Detroit on Christmas Day.