Multiple European flights targeted by bomb threats for second time this week

Several flights across Europe have been targeted by bomb threats for the second time this week.

Flights bound for Italy, Poland, Bulgaria, Austria and the Czech Republic have been affected, including an Aer Lingus plane which departed Dublin for Rome but was forced to divert to Evreux air base in northern France on Thursday morning.

Italian fighter jets escorted a Finnair flight travelling from Helsinki to the Italian capital, where it landed as scheduled.

It comes just days after eight European flights, including two from the UK, were targeted by suspected bomb threats. No explosives were found on any of the planes after searches.

The EU's transport commissioner, Apostolos Tzitzikostas, said it was not yet clear whether the incidents were linked.

"Any threats against civilians are unacceptable," he said.

The UK Transport Secretary Heidi Alexander described the incidents as "malicious hoax threats."

The airport authorities in Rome have said the hoax threat against two inbound flights received on Thursday came by email.

The warnings were signed on behalf of a group or individual calling themselves "Fighters of the Male State", claiming to be targeting a "feminist regime" and wanting to "make our mark on history".

They threatened to "turn the skies red" with explosions.

These details were first reported by Italian media and then confirmed to the BBC by Aeroporti di Roma, which manages both of the city airports.

The following flights were targeted by threats on Thursday:

• An Aer Lingus flight EI402 from Dublin to Rome diverted to Normandy this morning as a security precaution", the airline said, adding that it landed safely and it was working to "re-accommodate customers to their final destination as soon as possible".

• Two Finnair flights which departed Finland's capital, Helsinki, landed at their destinations as normal, the airline said. One was escorted into Rome's Fiumicino airport by Italian Air Force fighter jets, Aeroporti di Roma told the BBC, while the other landed in Vienna, Austria

• Wizz Air said two flights which departed Milan, northern Italy, were affected - one was heading to Warsaw, Poland before diverting to Vienna; the other landed safely at Bucharest's Henri Coandă Airport, with teams inspecting the aircraft

• Polish airline LOT flight from Warsaw to Brussels, Belgium, landed as planned - the airline said "no suspicious items were found". Another LOT flight from Warsaw to Paris was stopped on the runway before take-off and the plane and baggage underwent a security screening, with no hazardous items found

• Three Ryanair flights have landed in Bulgaria, according to Bulgarian media - one from Copenhagen and another from Madrid landed in the capital Sofia, while a third coming from London bound for Sofia landed in Plovdiv. The flights were escorted by Bulgarian air force fighter jets

• No explosives were found on four flights which landed in Prague, Czech police said

• An Aegean Airlines flight from Thessaloniki, Greece, and a Ryanair flight from Porto in Portugal landed safely in Milan as planned, with bomb disposal experts checking them on arrival, Italy's Ansa news agency reported

Philip Baum, professor of aviation security at the University of Coventry, said the industry "faces multiple bomb threats every single day" but he had been "surprised" by this week's incidents.

A flight is diverted "only when the threat is credible and the authorities believe there is a potential of explosive device on board", he said.

He said the concern was that "if you issue enough hoax threats, then complacency could set in and a real threat could be ignored - or they could be a diversion".

Marco Chan, an aviation expert at Kingston University, told the BBC the threats were "most likely a hoax, but the system is right to treat it as real".

He said they were being viewed by some experts as "possibly part of a pattern of cheap, deniable disruption" to air travel.

Hoaxes can also come from copycats, he said, but "three days of incidents is too small a sample to separate coordination from contagion".

On Tuesday, seven planes were searched after bomb threats were made.

Two were from the UK - one travelling from Manchester which landed in Murcia, Spain, the other from London Heathrow to Warsaw, Poland.

Two Ryanair flights - one leaving Dublin and the other from Lisbon - were searched after landing in Rome following anonymous tips but no explosives were found, sources at the city's Fiumicino airport told the BBC.

On Monday, a Wizz Air flight travelling from London Luton Airport to Sofia was escorted by a Hungarian fighter jet to Budapest after a mid-air bomb threat.