Russian GPS jamming is suspected of sabotaging the European Commission chief Ursula von der Leyen's jet on the way to Bulgaria.
The plane carrying the EU chief was forced to land at Plovdiv on Sunday using only paper maps, when a suspected Russian interference attack suddenly disabled the GPS navigation system.
Three officials brief on the incident told the Financial Times that the incident was likely the work of a Russian sabotage operation.
GPS 'jamming' or 'spoofing', which disrupts access to the satellite-based navigation system, is a tactic Russia has previously used to wreak havoc with civilian life.
The technique has historically been employed by military and intelligence services to protect sensitive locations.
