South Korea is considering the purchase of the Israeli electro-optical Sky Spotter system, which helps detect and track aerial objects, such as drones, the South Korean Yonhap news agency reports citing a defense source in Seoul.

In the coming weeks, the South Korean military plans to decide whether to formally request the purchase of the system following a review of its effectiveness in countering Pyongyang's alleged "drone threats," Yonhap said on Sunday.

This comes two days after South Korea's military claimed that a DPRK drone violated the vital no-fly zone around the presidential office last month, during a rare incident it had previously denied.

On December 26, South Korean news agency News1 reported that five drones that crossed the Korean military demarcation line "violated" South Korean airspace.

At the time, the drones were described by South Korean Joint Chiefs of Staff as no bigger than two meters in size. After failing to shoot down any of the drones, South Korea's military apologized.

"It is not true that (the North Korean drone) did not pass over Yongsan," Lee Sung-jun, a spokesperson for the Joint Chiefs of Staff said, in reference to the area where the presidential office and Defense Ministry are located.