North Korea has been jamming Seoul’s Global Positioning System (GPS) signals since last month, according to South Korean officials.
The signals began last week and continued on and off till February 6, Yonhap news reported quoting the military and information and communication technology (ICT) sector officials as saying.
"An assessment showed that North Korea's near daily GPS-jamming activity seems to be targeting aircraft navigation equipment," an intelligence source said.
The ICT officials said the jamming attack has not led to any major GPS disruption locally as of last Tuesday, although a total of 962 airplanes have been exposed to the malicious signals.
In the GPS disruption campaign so far, the North has broadcast jamming signals on a total of 100 occasions and, at their maximum output, reached more than 45 decibels, the official said.
The strength of the signals is constantly lessening or increasing in what appears to be a new type of assault operation, according to the official.
Nearly 700 fishing ships have been subject to the signals as well, while a total of 1,786 mobile Nearly 700 fishing ships have been subject to the signals as well, while a total of 1,786 mobile telecommunication base stations have been exposed.
Officials said North Korea had previously launched similar jamming assaults three times between 2010 and 2012, which partly disrupted the GPS-guided navigation of some 1,000 passenger jets as well as of the military's unmanned aerial vehicles.
Amid a heightened alert over the jamming, ICT Minister Choi Yang-hee inspected the military's readiness to counter potential North Korean cyberspace assaults.
Choi visited the military's Cyber Command earlier in the day and urged its resident experts to maintain "watertight" cybersecurity readiness, the defense ministry said in a statement.
He also called for more security measures to better detect and prevent any cyberspace attacks before they actually occur.
Last week, South Korea warned Pyongyang to immediately stop the GPS jamming operation, which it said is in violation of international rules and can endanger the lives of ordinary people.