Pyongyang has accused the US of violating its airspace in a series of critical comments about alleged air espionage, threatening reprisals. Seoul, meanwhile, spoke of routine flights over open waters.
Ednews informs via foreign media that Kim Jong Un's powerful military sister, Kim Yo Jong, alleged on Tuesday that a United States spy plane entered North Korea's exclusive economic zone eight times.
She claimed the "illegal incursion" by the US Air Force plane happened over the ocean 435 km (270 miles) east of Thongchon in Kangwon Province.
Washington has not commented on the claims by Pyongyang.
Kim warned the US would "experience a very critical flight" if it continued with the alleged incursions, according to the state-run KCNA news agency.
South Korea's military said earlier that the aircraft were conducting "normal" flights over open seas.
Kim said Seoul should refrain from interfering in what she considered to be a dispute between North Korea and the US.