Several passenger planes across Europe have been subjected to bomb threats, prompting emergency landings and security inspections in Poland, Spain and Bulgaria.
Two aircraft were inspected in Warsaw, Poland, while a third underwent security checks in Murcia, southern Spain.
Bulgarian media have also reported that a flight from Israel landed at Sofia Airport after an email containing a bomb threat was received.
One of the affected flights, travelling from London Heathrow to Warsaw Chopin Airport, was diverted to Warsaw Modlin Airport, where specialists inspected the aircraft.
The plane was carrying 181 people.
A second flight travelling from Copenhagen to Warsaw Chopin Airport also received a bomb threat but landed as scheduled, according to Danish media reports.
Meanwhile, a Ryanair flight from Manchester made an emergency landing at Murcia Airport following another threat.
Spanish government representative in the Murcia region, Francisco Lucas, confirmed that 121 people, including crew members, were on board.
The incidents come a day after a Wizz Air flight from London Luton was forced to make an emergency landing in Budapest, Hungary, under escort from a Hungarian fighter jet following a bomb threat.
Investigations into the separate incidents are ongoing.