North Korea is in the process of developing a long-endurance aerial drone, the government said Sunday.

The unmanned aerial vehicle (UAV) that is undergoing flight testing is larger than those currently in service in the North, an official source said. Last week the North's Chosun Central TV revealed that a new type of UAV is under development.

The media outlet did not provide clear images of the drone but claimed it had real-time observation and tracking capabilities. It also said the machine can be used to check the atmosphere and detect forest fires.

"The North is building larger drones with greater range and with the capability to be flown remotely by flight controllers," an official from Seoul's defense ministry said. He declined to go into detail but said Seoul has detected numerous test flights by such aerial vehicles since early this year.

South Korea estimates that the North has some 300 observation drones and around 10 machines capable of conducting attacks.

Local military experts also said that based on the information provided, the North may be upgrading drones it initially brought in from China and the Soviet Union in the past by making them bigger and more useful in terms of range and capabilities.

"The North clearly seems to be interested in building its own UAW to replace the old imported machines and copies of these drones that have crashed in South Korean territory in the past," a Korea Defense and Security Forum source said. (Yonhap)