BRUSSELS, Nov. 5 (Xinhua) -- Onboard bomb threats affected multiple passenger flights across Europe on Thursday, causing extensive disruptions, while some flights have already landed safely.

Three flights operated by the Irish airline Ryanair from Copenhagen, Madrid and London to the Bulgarian capital Sofia received bomb threats before safely landing, Bulgarian media reported.

Security checks found no dangerous objects on board any of the flights, with investigations ongoing and heightened security measures at the affected airports, the media reports said.

Meanwhile, a LOT Polish Airlines flight from Warsaw landed safely at Brussels Airport after a suspicious report concerning the aircraft, Belgian news outlet BRUZZ reported, citing Belga News Agency.

Following a similar suspicious report, the airline's Paris-bound flight LO331 was stopped while taxiing at Warsaw Chopin Airport, Polish broadcaster TVN24 reported.

Security checks found no dangerous items, and LOT said the flight would continue on a replacement aircraft.

Also on Thursday, bomb alerts were reported involving three passenger flights departing from or bound for Italy, prompting the flights to divert or receive a military escort, Italian news agency ANSA reported.

The affected Aer Lingus Airbus A320 flying from Dublin to Rome was diverted to the French air base in Evreux before being escorted by a French Rafale fighter jet. All 151 passengers and six crew members were reported safe, with bomb disposal teams preparing to inspect the plane.

A Hungarian Wizz Air Airbus A321 heading from Milan to Warsaw was diverted to Vienna, Austria. The unscheduled landing followed an email containing a vague threat, Austrian newspaper Kronen Zeitung reported. Passengers were questioned individually and their luggage checked, while long queues formed at security checkpoints, although screening continued to proceed relatively quickly, the newspaper reported.

A Finnair flight from Helsinki to Rome was escorted by Italian Air Force fighter jets. A separate flight from Helsinki to Vienna, operated by Jettime on behalf of Finnair, also received a threat but landed as scheduled, according to the Finnish airline.

Czech police said on Thursday in an X post that they were working with Prague Airport to prepare for the landing of four aircraft after receiving a bomb threat involving explosive devices allegedly planted on board. They assessed the credibility of the threat as low.

Shortly afterward, Czech news agency CTK quoted a police spokesperson as saying no explosives were found on board any of the four flights.

Bulgarian media reported Thursday that some flights in Europe have received bomb threats since the beginning of the week, including two bound for Sofia on Tuesday, with checks having found the bomb threats fake.