SEOUL - Government officials here accused North Korea on Wednesday of sending out jamming signals in an apparent attempt to disrupt civilian and military air and ground traffic in South Korea, forcing 252 commercial flights to switch off their global positioning devices.
The North has tried to sabotage South Korea’s use of the global positioning system, widely employed in air, sea, and ground navigation, at least three times since 2010, the Korea Communications Commission said.
The commission said the latest jamming began Saturday, after North Korea’s recent warnings of “special actions’’ to attack the government of President Lee Myung Bak in South Korea and the South’s conservative media, which the North accuses of slandering its leadership.
“We believe that the jamming signals originated in North Korea,’’ said Chun Young Soo, a commission official. “But there has been no damage reported.’’
The jamming was focused largely on air traffic at Incheon and Gimpo International airports, which are just west of Seoul and about 30 miles from the border with North Korea.
Flights using those airports were instructed to switch to alternate navigation systems and were operating on schedule, the Ministry of Land, Transport and Maritime Affairs said.
Chun said it was easier to interfere with GPS devices in the air than on the ground, where buildings and mountains can block the jamming signals.
The disruption affected 241 South Korean flights as well as 11 operated by FedEx, UPS, Japan Airlines, Thai Airways, Cathay Pacific Airways, and Air Philippines, said Sohn Dong Hwan, a ministry official. Few other disruptions were reported.
The government issued a notice for pilots and airlines Saturday after it detected the jamming signals.
South Korean military transportation was not affected because it does not rely primarily on the GPS, said a Defense Ministry official, who discussed the matter with reporters on the condition of anonymity, citing ministry policy.
Last month, North Korea threatened to turn Lee’s government and conservative media in Seoul “to ashes in three or four minutes’’ using “unprecedented peculiar means and methods.’’