The situation on the Korean Peninsula has become extremely tense due to the drone.
North Korea said the reappearance of a South Korean drone in its airspace would be considered a declaration of war.
The warning was issued by a North Korean Defense Ministry spokesman and broadcast through the Korean Central News Agency, KCNA reports.
Pyongyang believes the South Korean military may be involved in the drone's creation, the spokesman said.
He stressed that another appearance of a DPRK UAV will be considered as having arrived from the Republic of Korea.
The department explained that the measures would be taken in response to the serious situation in the area of the republic’s southern border.
North Korea has previously launched garbage balloons toward South Korea. In response, Seoul has been broadcasting slogans over loudspeakers every day.
The DPRK General Staff also added that it plans to strengthen security to strengthen the border.