Russia shut down GPS navigation services at the Bulgarian airport in Plovdiv on Sunday, three unnamed officials told the Financial Times on Monday. European Commission President Ursula von der Leyen was due to land there at the time. Her plane had to land using traditional paper maps, TASR reports.

Ursula von der Leyen's plane first circled the airport for an hour

"The entire airport area was left without GPS signal," one source said. After circling the airport for an hour, the pilot of the EC President's plane decided to land manually using analogue maps. According to sources, they are currently working on the version that Russia was behind the signal jamming.

Von der Leyen met with Prime Minister Rosen Zhelyazhkov and visited a munitions factory in Bulgaria as part of her tour of eastern EU countries. She departed on the same plane and there were no further incidents.

"We can confirm that there was GPS interference, but the plane landed safely in Bulgaria," European Commission spokeswoman Arianna Podesta told a press conference in Brussels. The EC has already received information from Bulgarian authorities that they suspect Russia of being behind the incident.

Russia also uses GPS signal jamming to disrupt civilian life

The FT notes that GPS jamming is often used by militaries and intelligence agencies to protect sensitive locations, but Russia has also recently used the tool to disrupt civilian life.

Similar incidents have occurred mainly in the Baltic Sea and Eastern European countries near Russia. In addition to aircraft, ships and civilians using regular navigation services have been targeted. Some EU governments have already warned that Russian interference could cause an air disaster.

"We are well aware that threats and intimidation are a common part of Russia's hostile actions," Podesta added, adding that the incident would further strengthen the EU's resolve to strengthen its defense capabilities and support for Ukraine.