A spate of bomb threats across Europe has thrown airports and newsrooms into disarray over the past week, forcing flight diversions and emergency landings while prompting broadcast suspensions and evacuations to conduct security sweeps.

No explosives have been found, and the threats have so far proved unfounded. But the spate of hoaxes that affected a number of flights, airports and, as of Friday, news broadcasters has raised concern over the widening impact if the threats continue to spread.

It's not yet clear if the incidents are linked, but the bomb threat hoaxes come on the heels of other European disruptions, including attacks on supermarket refrigeration systems drone incursions Here is what we know about the hoaxes targeting airlines and broadcasters in Europe. When did the threats begin? What appeared to be a co-ordinated wave of bomb threats targeting European air traffic began on Tuesday. At least seven flights and a cruise ship received hoax bomb threats triggering emergency landings, fighter jet escorts and temporary airport closures in countries including Poland, Bulgaria, Italy and Spain.

A second wave was reported on Thursday, with at least 27 flights affected Bomb threats force multiple flights in Europe to make emergency landings November 5 Duration On Friday, Prague's Vaclav Havel Airport said a total of nine flights were threatened, including arriving flights from Denmark, Spain and Britain, and departing flights to the Netherlands, Cyprus, Romania, Italy and Britain.

How are newsrooms involved? Newsrooms in Ireland and Bulgaria received emailed bomb threats on Friday from a purported "Mikhail Andropov" claiming responsibility for a widening wave of hoax threats disrupting passenger flights across Europe.

The messages, sent to Bulgaria's Nova TV and the Irish public broadcaster RTE, which evacuated its offices and suspended programming, were headlined "Message to the West" and portrayed the threats as the prelude to a series of attacks on means of transport across Europe.

The British broadcaster Sky also said it had received a security threat. Reuters was not able to establish the identity of the sender, the origin of the emails or whether they had in fact come from the same source as the threats to any or all of the dozens of flights affected since Tuesday. How are the threats sent?

Bomb threats against planes are often communicated to airlines, airports or authorities through anonymous emails or phone calls claiming that an explosive device is on board. Authorities do not always disclose how threats are delivered, because doing so could encourage copycats and compromise investigations.

A Prague airport representative told CNN on Thursday that they had received a threat from an anonymous email addressed to the airport, and Czech police said similar emails went to other European airports. Eric Schouten, head of aviation security group Dyami, told Reuters that an airline's security department first runs the report through a checklist.

It then alerts the authorities, who may scramble fighter jets or divert the plane to a designated airport for a full sweep.

What are the risks? The vast majority of bomb threats turn out to be false alarms, though all must be treated as real until investigated, which means authorities are forced to scramble to rule out any danger.

No explosive device has been found on the planes affected this week, but every airline must decide whether a threat is credible and act accordingly.

A spokesperson for the British government called this week's incidents "malicious hoax threats" and said it has "one of the most robust aviation security systems in the world."

String of bomb threats on flights, cruise ship disrupt travel across Europe Bomb threats affect at least 27 flights, leading to emergency landings at several European airports Airlines are not new to bomb threats, but aviation security experts say the apparent co-ordination and timing of the current incidents is unusual. All planes, including those threatened on Friday, landed safely. Who is behind the threats? Authorities have not attributed the threats to any group or state actor, and no evidence has emerged linking the hoaxes to a government.

The incidents come at a time when many European officials have accused Russia of a campaign of "hybrid" or "grey zone" disruptions that are essentially cheap to execute, easy to deny and not expected to trigger an armed response.

Countries affected by the disruptions, including Denmark, Poland and Romania, have previously accused Moscow.

Russia denies any involvement. On Thursday, an airport source in Italy said bomb threats had been sent to several airlines and airport operators in Rome and Milan purporting to be from "fighters of the Male State," a far-right anti-feminist movement banned in Russia.

Reuters could not confirm who had sent the email.

Vladislav Pozdnyakov, a Russian blogger who set up Male State in 2016, said it no longer existed and was not involved in any way. What is their goal? Rhys Jones, analysis output manager at aviation risk advisory firm Osprey Flight Solutions, said bomb threats can stem from a wide range of motives, including political grievances, activist campaigns, criminal activity, online groups or state-linked hybrid operations.

European technology commissioner Henna Virkkunen says that since 2022, Europe had faced a range of hybrid operations, including sabotage of critical infrastructure, drone incursions, cyber breaches and election interference.

“We are under attack all the time,” she told Reuters.

“The reason behind these operations is to destabilize our societies and create mistrust among our citizens.”“It’s not always Russia who is behind different hybrid operations. Quite often, it is Russia.”

How have airlines been affected?

Overall, the threats have caused minimal disruption to aviation, according to Eurocontrol, the European air traffic authority.

Even a false alarm can disrupt airlines' operations, with plane diversions and thorough security inspections causing delays for passengers. Carriers typically bear additional costs including fuel, passenger rebooking, crew disruption and aircraft diversions.

Schouten said a sweep means unloading passengers and baggage, searching the aircraft and reloading. That can push crews past duty limits and lead to missed connections and cancellations.

Air France-KLM chief executive Ben Smith said on Thursday he had never previously seen threats reported in such a co-ordinated fashion.

"We're quite confident that we have in place what we need to ensure that it has minimal or no impact on our operation," Smith told reporters. "So we have no ask today of our governments to change the way they manage these types of situations." Which airlines, airports have been affected? Copenhagen Airport Warsaw-Modlin Airport Warsaw-Chopin airport Prague Airport Aegean airlines Aer Lingus Air Europa Air Serbia Austrian Airlines EasyJet Finnair LOT Polish Airlines Ryanair SAS Scandinavian Airlines Wizz Air What measures are being taken?

Bomb threats are on pilots' minds and create unnecessary tension, but crews are prepared to respond professionally, said Paul Reuter, vice-president of the European Cockpit Association.

Pilots review procedures with cabin crews, identify airports where they could divert and may carry extra fuel, he said.

Reuter called the use of civil aviation for geopolitical disruption or hoaxes "totally unacceptable."