A fresh wave of bomb threats disrupted air traffic across Europe on Friday but the affected aircraft landed safely and searches revealed no explosive devices.
The latest alerts affected at least 18 flights to or from Bulgaria, Cyprus, Czechia, France, Hungary, Italy, Portugal, Romania and the UK.
Danish police investigated a threat against Copenhagen airport but the airport’s management said it was operating normally.
The warnings followed separate threats on Tuesday and Thursday that forced at least 35 flights to be diverted or searched, raising questions over an apparently coordinated effort to cause chaos for travellers.
A number of European media outlets – including news organisations in Bulgaria, Ireland and the UK – have reported that a group claiming responsibility for this week’s threats sent an email to several outlets warning of further attacks on transport across Europe.
“This is only the beginning,” it reportedly said.
The latest threats affected at least nine flights to and from Prague, four flights over France, two flights en route to Sofia and a flight from Lisbon to Rome. Hungary scrambled fighter jets three times to escort civilian flights in its airspace, the defence minister, Romulusz Ruszin-Szendi, said on Facebook.
The affected flights had knock-on effects but were a tiny percentage – just 0.0674% – of the 26,709 flights that according to the air traffic control agency Eurocontrol were scheduled in Europe on Friday.
A separate spate of threats on Friday against media organisations in Ireland disrupted broadcasts and prompted staff evacuations and police searches of offices and newsrooms.
The taoiseach, Micheál Martin, told RTÉ Radio 1 after it resumed scheduled broadcasting that such threats had to be taken seriously and were an effort to sow fear and anxiety.
“It shows how relatively simple it can be to cause disruption and undermine the normal operation of society,” said Martin, adding that European security agencies would seek to identify those responsible and hold them accountable.
The British broadcaster Sky said on Friday it had also received a security threat and reported the matter to the relevant authorities.
Earlier this week, cyber-attacks targeted supermarket refrigeration systems in at least seven European countries.
The Italian prime minister, Giorgia Meloni, said it was unclear whether the hoaxes and recent cyber-attacks were “all connected”.
She added: “But they definitely all tell us the same thing: today, what is under attack are civilian infrastructures.”
The Nato alliance continued to monitor the situation and was working closely with allies, according to a senior Nato military official.
Investigators have said there was no evidence that hoaxes against airlines and other targets were being orchestrated by a hostile terror group or state actor, such as Russia or Iran, but that inquiries were continuing.
Several European media outlets in Bulgaria, Ireland, the UK and elsewhere reported that a group claiming responsibility for this week’s threats warned in an email of further actions against transport across Europe.
“This is only the beginning,” it reportedly said. The Guardian has chosen not to reproduce the email in full, given its unsubstantiated claims.
Some of the threats on Thursday were signed “fighters of the Male State”, a reference to a Russian far-right, ultranationalist and misogynistic movement founded in 2016. In a Telegram post on Friday the group’s founder, Vladislav Pozdniakov, denied involvement and said the group had not existed since 2021.
Some officials suspect the waves of disruption are linked to European support for Ukraine in its war against the Russian invasion.
Spain’s foreign minister, José Manuel Albares, said authorities needed more time to identify culprits but that there appeared to be a pattern.
“It cannot be mere coincidence that so many incidents with exactly the same modus operandi are happening across Europe,” he told the national broadcaster TVE.
“The most reasonable assumption is that we are facing an attempt at hybrid aggression and a form of psychological warfare,” he said, adding that Europe must be prepared for more such challenges.
Mark Rowley, the chief of London’s Metropolitan police, urged a measured response, saying past experience with the paramilitary Irish Republican Army offered valuable lessons.
He recalled the phrase “10p terrorism”, when a hoax bomb call made from a coin-operated phone box could disrupt an entire city, forcing authorities to distinguish between genuine and false threats.
The authorities would need to adapt to an evolving threat landscape involving actors around the world, some backed by hostile states, he said.
“We are going to have to adapt to that same methodology to make sure that we don’t overreact to every message we get online,” he told BBC Radio 4.
