The country’s joint chiefs of staff, Lee Seung-o, claimed that the “unmanned aerial vehicles” breached South Korean airspace in the border regions near Gyeonggi Province.
Before retreating across the border, one drone travelled as far north as Seoul, the capital.
Despite the deployment of jets and assault helicopters, 100 rounds from the helicopters’ cannons were ineffective in bringing them down.
Although they had already lost track of all the drones, a military spokesman from South Korea claimed that they were no longer in flight.
The South Korean military responded by claiming that it had also flown surveillance planes into the North to take pictures of its military facilities.
In June 2017, five years ago, when tensions between the two Koreas were at their height, a North Korean drone last crossed the border.
Drones from North Korea represent a threat to the security of South Korea because they might be used to spy on the South as well as launch an assault on it.
The North claimed earlier this month to have conducted significant experiments that would aid in the development of its first spy satellite, which could be used to keep an eye on South Korea. It published an aerial image of Seoul that it claimed to have captured during the test.
Since a new, conservative government gained office in South Korea and North Korea continues with its nuclear and missile programmes, the already strained relations between the two countries have gotten even worse. South Korea is a close ally of the United States.
In response to a record number of North Korean missile tests this year, South Korean and American forces have ramped up military drills. Such drills have been seen as invasion preparations by North Korea.