Bomb threats targeted seven passenger planes across Europe, two of which departed from UK airports, according to the BBC. Authorities inspected the aircraft, and none were found to contain explosives.
Two Ryanair flights, one from Dublin and one from Lisbon, were searched after landing in Rome following anonymous tips, sources at Fiumicino airport told the BBC. The Dublin flight was escorted by the Italian air force until it landed. Police bomb disposal experts carried out standard security protocols, and the alert has since been cleared.
Authorities also searched planes in Poland, Spain and Bulgaria. A Ryanair flight from Manchester landed in Murcia, Spain, where Spanish authorities said no explosives were on board. Two flights bound for Warsaw were affected, including one from London Heathrow that was diverted to Modlin airport. Bulgarian Transport Minister Georgi Peev said threats were made against two planes travelling to Sofia, and the flights were not diverted.
It is unclear whether the incidents are connected. Officially, there is no link between them, but authorities from various countries will cooperate to assess whether they were a coordinated attack designed to disrupt airspace.
The UK government described the incidents as "malicious hoax threats." It said the UK has "one of the most robust aviation security systems in the world."
Aviation security expert Paul Mason told BBC Radio 5 Live that bomb threats on passenger planes "don't happen that frequently," and that the threats appeared to be made credibly across a broad range of airlines. He said that suggested "a very deliberate act by a typical actor."