A fresh wave of bomb threats targeted passenger flights across Europe today, for the third time in a week, as Spain’s Foreign Minister said the continent appeared to be facing “hybrid attacks and a form of psychological warfare”.

False bomb alerts disrupted passenger flights across Europe on Thursday, forcing some aircraft to make precautionary landings and requiring others to be escorted by fighter jets. The incidents marked a dramatic escalation following the first wave of threats on Tuesday.

No explosive devices were found on any of the aircraft, and all landed safely.

Denmark’s police said today that they were investigating threats to air traffic at Copenhagen Airport. However, an initial assessment found no danger to passengers, and the airport was “operating normally”.

Czech police said they had recorded bomb threats involving flights to and from Prague. An airport spokesperson said the threats concerned four incoming and five outgoing flights. No explosives were found, and no flights had to be cancelled or diverted.

A short while later, a source at the Italian airport authorities said a Wizz Air flight from Prague to Rome had been diverted to Venice, where it landed safely.

The office of the French Prime Minister announced that four further bomb threats had been made against aircraft flying over French territory. All landed safely.

A bomb threat against a Ryanair flight from Rome to Lisbon triggered a security operation after the aircraft landed, CNN Portugal reported.

Hungarian fighter jets escorted three passenger flights today after bomb threats were reported while they were flying through Hungarian airspace, Defence Minister Romulusz Ruszin-Szendi said in a social media post. He said the fighter jets accompanied an Airbus A321 travelling from Brussels to Sofia, as well as flights from Prague to Cyprus and Bucharest.

Two passenger aircraft arriving from London and Brussels landed safely at Sofia Airport today following bomb threats made by email, Bulgarian media reported. The aircraft were searched by border police and security personnel, but no suspicious objects were found, Bulgaria’s Transport Ministry told Nova TV.

The Dutch military police also announced that no explosives had been found on a KLM flight bound for Amsterdam that had received a bomb threat.

Threats bear hallmarks of a coordinated ‘hybrid’ attack

Security experts said on Thursday that the threats bore the hallmarks of a coordinated “hybrid attack”, although it remains possible that individuals were making copycat threats or acting out of personal grievances.

No country has attributed responsibility for the threats. However, they come amid a wave of sabotage attacks and attempted attacks on targets across Europe, ranging from German electricity substations and defence-related facilities in the Baltic region to supermarket refrigeration units in France and elsewhere, as well as Leipzig Airport in Germany.

Many officials have linked the campaign to Europe’s support for Ukraine in its war against Russia’s invasion, accusing Moscow of pursuing a campaign of “hybrid” disruption that is relatively cheap to carry out, easy to deny and unlikely to provoke an armed response.

Spanish Foreign Minister José Manuel Albares told national broadcaster TVE that, although it would take time to establish exactly what had happened, “it cannot be a mere coincidence that so many incidents with exactly the same modus operandi are taking place across Europe”.

“The most reasonable assumption is that we are facing an attempt at hybrid attacks and a form of psychological warfare,” he said, adding that Europe must be prepared for more such challenges.

On Thursday, a source at Italian airports said bomb threats had been sent to several airlines and airport operators in Rome and Milan, claiming to come from “fighters of the State of Men”.

Reuters was unable to independently verify who had sent the email, and there was no immediate evidence identifying those behind the other threats reported across Europe.

Vladislav Pozdnyakov, a Russian blogger who founded an anti-feminist movement called the “State of Men” in 2016, which was later banned in Russia, said the group no longer existed and had no involvement whatsoever.

Ireland warns of ‘possible coordinated campaign’

The Irish government announced today that it was “likely” that the bomb threats targeting media organisations in the country and passenger aircraft across Europe in recent days were part of a “coordinated campaign to cause disruption”.

Irish media outlets were evacuated today following false bomb threats.

“These threats come after similar disruptions to aviation in Europe, and it seems likely that this is a coordinated campaign to cause disruption,” the government said in a statement, adding that it did not yet know who was responsible.