North Korea has been jamming Global Positioning System signals in South Korea since last Friday, it emerged.
"The North kept jamming GPS devices as of Tuesday," a senior government official said Wednesday. "The attack isn't common knowledge because there's been no tangible damage, but it continues."
There was one report that the GPS equipment of civilian aircraft near Incheon International Airport was faulty last Sunday. The official added the government identified Kaesong and Mt. Kumgang as the sources of the jamming attack. Interfering signals are sent out constantly, "so we can't say exactly when and how many times it was carried out."
A senior Cheong Wa Dae official said it is "certain" that the North is behind the attack because the signal can be traced to its exact source. "The North should immediately stop the attack, which clearly runs counter to the spirit and charter of the International Telecommunication Union," the official added.
"It's a clear violation of international law, but no penalty clauses are clearly defined for this kind of attack, so the government is reviewing what kind of sanctions it could impose," presidential spokeswoman Kim Hee-jung said.
Meanwhile, Minister of Public Administration and Security Maeng Hyung-kyu said a cyber attack on Friday was "seven times" as intense as a similar one two years ago but was dealt with swiftly before it did much damage. "The attack was launched on the websites of 40 government agencies on three occasions. A total of 77,000 zombie computers infected by seven file-sharing sites were used for the attack," he told government officials and Grand National Party leaders.