REPORT: North Korea Has 1K Chemical Weapon-Capable Drones.

The warning came Thursday from Chung Ku-youn, a research fellow at the Korea Institute for National Unification, the Yonhap News Agency reported.

Because of its outdated aircraft, North Korea has focused on developing drones, the research fellow added. The development of various versions of the drones, known as “Banghyun,” have been under way since the early 1990s,Yonhap reported.

Recently, North Korea has developed a large stealth drone “Banghyun 5” that can carry explosive devices and radioactive materials, Kim Heung-Kwang, a defector and the head of a private think tank, said last year, Yonhap reported.

According to Business Insider, the first installment of Lockheed Martin’s F-35 Lightning II is scheduled to be delivered to South Korea in 2018 – a delivery that could make North Korea’s jets obsolete, and drone development more urgent.

Until then, the Pentagon announced that the Marines have dispatched eight F-35B fighters to South Korea, “where they will be permanently stationed and on call to respond quickly if a crisis occurs on the Korean Peninsula.”