Seoul suspects that four drones discovered in Two days later belong to South Korea . The unmanned aircraft are fitted with digital cameras , difficult to detect with radar . But it seems the North Koreans have reverse-engineered them with explosives , says Hardy . Experts say the drones are low-tech and pose little threat . North Korea is bolstering its air defense network in light of the discovery .
Seoul suspects that four drones discovered in Two days later belong to South Korea . The unmanned aircraft are fitted with digital cameras , difficult to detect with radar . Experts say the drones are low-tech and pose little threat . North Korea is bolstering its air defense network in light of the discovery .