North Korea has continued to jam satellite signals to try to disrupt air and maritime traffic navigation systems in South Korea, a government official said Sunday, in defiance of Seoul's warning to take the issue to a U.N. communications agency.

The North's global positioning system (GPS) jamming signals originating from its western border city of Gaeseong since April 28 have not caused damage to airplane flights or ship navigations in South Korea's border areas, the official said.

GPS is a satellite-based navigation system widely used by aircraft, ships and the military as well as private vehicle owners.

South Korean military fighters, cargo planes and precise guided bombs are not affected by the disruption of GPS signals as they are equipped with a military-only satellite navigation system, the official said on condition of anonymity, citing policy.

Kim Ki-hyun, a transportation ministry official, separately confirmed the jamming attacks were still taking place as of Sunday, but said they posed no safety threats to civilian flights as airlines use an alternative navigation system.

The jamming attacks had affected 609 flights operated by 10 South Korean airlines and 48 foreign flights of 22 foreign airlines, including Korean Air, FedEx, United Airlines and Delta Air Lines, up until May 9.

Kim said South Korea recently decided not to release further numbers of flights affected by the jamming attacks for security reasons.

The North's defiant move continued four days after South Korea urged Pyongyang to stop electronic jamming signals. South Korea also said it would push to raise the issue with the International Telecommunication Union (ITU) and the International Civil Aviation Organization.

South and North Korea are members of the ITU, the United Nations agency in charge of information and communication technologies, which bans harmful interference. (Yonhap)