An expert believes that the recent disruption of satellite navigation signals in South Korea was conducted by an affiliate of North Korea's Reconnaissance General Bureau (RGB).

Professor Lee Dong-hoon of Korea University’s Graduate School of Information Security made such an analysis at the 10th Defense Information Protection Conference hosted by the Defense Security Command on Thursday.

Professor Lee said that North Korea has been preparing for cyber attacks since the late 1980s. He also noted that the communist nation is the world’s third strongest power in terms of cyber warfare following the U.S. and Russia. He believes that based on news reports from both home and abroad, it is very likely that the recent disruption was carried out by the cyber warfare unit of the North’s RGB.

The cyber warfare unit is known to be in charge of intruding into computer networks, hacking confidential data, and distributing viruses. Around three-thousand agents are believed to be working in the unit, who are under the direct control of the North’s leader Kim Jong-un and the head of the RGB, Kim Young-chul.