There were no casualties or damage to infrastructure, Radev said, adding that the device had detonated in a sunflower field near the former Kardam border crossing between the two EU and NATO countries, about 1 kilometer from a Trans-Balkan gas pipeline compressor station. “Sound from the drone was detected by Romania’s Border Police, followed by a loud explosion heard by the [Bulgarian] border patrol from General Toshevo, which is stationed in the area,” Radev was quoted by the state-owned Bulgarian news agency BTA as saying. “The location of the drone explosion was immediately identified, and teams from the Border Police, National Police and the Defense Ministry are currently at the site to determine the type of drone involved.” Not detected by air defenses Speaking after an emergency meeting of Bulgaria’s Security Council on Saturday morning, Radev said the drone had not been detected by either Romanian or Bulgarian air defense systems, which he attributed to its small size. “When flying at low altitude, it is not possible to ensure sufficiently dense radar coverage,” he said. “We have also received no information from the Combined Air Operations Center in Torrejón [Spain], which monitors the airspace across southern Europe,” Radev added. The prime minister also said border guard personnel and equipment used to detect and counter drones would be redeployed from the Turkish border to the Romanian border. Radev said the drone had been carrying a substantial explosive payload, but that its origin had not yet been determined.