South Korean authorities said North Korea is using so-called radio jammer to suppress GPS navigation systems in border areas.
According to the authorities, it started about a month ago in several places at once along the border, but stopped last Thursday.
This reportedly led to disruptions in the navigation systems of 110 ships and aircraft, as well as to interruptions in mobile telephony.
A spokesman for the South Korean ministry for the unification of the two countries called these actions by Pyongyang a provocation, Agence France-Presse reports.
South Korean media report that Seoul has accused its northern neighbor of jamming GPS signals for at least the fourth time since 2010.
At the same time, it is reported that, most likely, the equipment for signal suppression was supplied to the DPRK from Russia.
On Friday, the South Korean military reported that the DPRK had once again launched a ballistic missile at sea, despite international sanctions and criticism from world powers.
Last week, North Korea announced an artillery exercise simulating an attack on the official residence of the South Korean president.