An aircraft carrying European Commission President Ursula von der Leyen was allegedly hit by Russian GPS jamming on its way to Bulgaria, the commission said Monday.
"We can confirm there was GPS jamming but the plane landed safe," a commission spokeswoman said about the Sunday incident. "We have received information from Bulgarian authorities that they suspect this blatant interference was carried out by Russia."
"We are well aware that threats and intimidation are a regular component of Russia's hostile actions," the spokeswoman added.
"This will further reinforce our unshakable commitment to ramp up our defence capabilities and support for Ukraine."
Von der Leyen was travelling to Bulgaria on Sunday on a charter flight.
According to the Financial Times, the plane had to remain in the air for around an hour longer than planned due to the GPS malfunction.
The pilot then made the decision to land manually in the city of Plovdiv with the aid of analogue maps.
The airport director, Krassimir Peshev, said there was no danger to the lives of the passengers and that it is usually not a problem to land in Plovdiv, Bulgaria's second largest city, without GPS navigation.
It is routine practice to use another system if there are problems with one landing system, Peshev said on state radio.
Plovdiv is some 130 kilometers south-east of Sofia. Its airport is used by low-cost airlines and for charter flights.
Von der Leyen has been visiting countries in the north and east of the European Union over the past few days.
After arriving in Bulgaria on Sunday, she met with Prime Minister Rosen Zhelyazkov to discuss European security and defence issues, and visited the largest state-owned arms manufacturer.
Political talks on von der Leyen's tour were to focus primarily on deterrence and defence initiatives against Russia, which could have been a possible reason for the attack, sources in Brussels said.
Bulgaria is also a major supplier of weapons to the Ukrainian military, providing one-third of supplies at the beginning of Russia's full-scale invasion, according to von der Leyen.
Kremlin spokesman Dmitry Peskov rejected the accusations against Russia in comments to the Financial Times.
Disruption to GPS satellite navigation in eastern Europe is nothing new. Last year, Estonia summoned the chargé d'affaires of the Russian embassy in Tallinn after GPS interference led to the temporary suspension of air traffic between Finland's capital Helsinki and the Estonian city of Tartu.
German Navy Inspector Christian Kaack said GPS interference is commonplace against both military and civilian targets.
The German military's inspector general, Carsten Breuer, described his own experiences with GPS jamming, once during a flight over the Baltic Sea and again during a visit to a military exercise in Lithuania.
While pilots usually have the ability to circumvent such interference, Breuer stressed: "We are currently under constant sabotage and espionage, and we are also subject to hybrid influence and hybrid actions, which we can very often trace back to state actors and, in many cases, to Russia."
