A plane carrying the European Commission President Ursula von der Leyen was targeted by GPS navigation jamming while trying to land in Bulgaria on Sunday, a spokesperson for the commission told CNN.

NATO is working to thwart Russian jamming of civilian flights, said the alliance's chief on Tuesday, two days after a jet carrying European Commission President Ursula von der Leyen lost its ability to use GPS navigation midair in Bulgarian airspace.

A plane on which European Commission president Ursula von der Leyen was travelling was hit by GPS jamming over Bulgaria in a suspected Russian operation, a spokesperson says. The plane landed safely at Plovdiv International Airport in the country’s south-central region on Monday.

Russian foreign ministry's spokeswoman Maria Zakharova said on Thursday that allegations about Russia being behind jamming the European Commission President Ursula von der Leyen's airplane were fake and paranoia.

Bulgarian authorities aren’t investigating a suspected Russian interference operation involving a plane carrying European Commission President Ursula von der Leyen because they say the interference is

While von der Leyen's plane landed safely, Rutte said the entire continent is now under direct threat from Russia's escalating tactics.

A plane carrying European Union chief Ursula von der Leyen was forced to land in Bulgaria using paper maps after its GPS navigation systems were jammed. Jamming has become an "invisible threat that risks devastating air travel" and leaves civil aircraft "one step away from disaster",