For more than three years, Ukraine has been battling Russian attack drones.

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 now common.

Ukraine said its “Operation Spiderweb” attacked Russian warplanes worth hundreds of millions of dollars, utilizing drones that each cost under $1,000 and were launched from wooden containers carried on trucks.

Serbia's populist government is facing increased public scrutiny over reports that it used a sonic weapon against a peaceful crowd during a massive anti-corruption rally in the capital, Belgrade, on March 15.