Authorities in North Korea instituted a near-total block on the use of illegal cell phones which access Chinese telecom networks during South Korean President Moon Jae-in’s visit to the capital Pyongyang this week through increased surveillance and jamming technology, according to sources.



North Koreans who live in border areas where Chinese networks are available use smuggled cell phones to call family members living in China or South Korea and surf the internet, which Pyongyang prevents its citizens from accessing. Authorities often deploy “jammers” that block the network signals and locators to determine a phone’s whereabouts, both through the use of radio waves.



But sources in China, across the border from North Korea, told RFA’s Korean Service that authorities in the North virtually shut down access to the networks ahead of Moon’s Sept. 18-20 visit with North Korean counterpart Kim Jong Un—the third summit on denuclearization between the heads of the rival nations this year—to block out foreign media coverage of the event.



“Mobile communication with [North Korea’s] Sinuiju city, right across the river from [China’s] Dandong city, is completely blocked,” a resident from Dandong told RFA on Wednesday, speaking on condition of anonymity.



“North Korean residents in the border area are just waiting for the South Korean president’s Pyongyang visit to be over, with their mobile phones turned off [to avoid detection].”



According to the source, “special inspection teams” were dispatched to Sinuiju on Sept. 17, and that Chinese traders are “having a hard time” because they have been unable to communicate with their partners across the border.



“It’s not surprising that North Korean authorities are cracking down on illegal mobile phones,” the source said.



“However, since they sent special inspection teams from Pyongyang, they clearly intend to completely block any communications with the outside world during the South Korean president’s visit.”



A source from Yanji, a city in China’s Jilin province near the border with North Korea, told RFA he had heard crackdowns on illegal cell phones on the North’s side of the Tumen River, which separates the neighboring nations, had “intensified.”



“[China’s] Changbai county [in Jilin province] and [North Korea’s] Hyesan [city in Yanggang province] are so tense that one barely sees any cars or people around,” said the source, who also asked to remain unnamed.



“This strict situation is probably due to North Korean authorities’ security measures for the South Korean president’s Pyongyang visit. Chinese residents of the North Korea-China border area who make a living doing business with North Korea wish for Moon’s visit to end as soon as possible.”



The source said that a friend from Jilin’s Antu county had told him that only border crossing between the two nations by land, across North Korea’s sacred Mt. Paekdu—known in China as Mt. Changbai—had been closed from Sept. 17-21.



“We couldn’t understand why they suddenly closed down the entrance, but now we know that it was because of Moon’s visit to Mt. Paektu,” he said.



Summit conclusion



Moon and Kim wrapped up this week’s summit on Wednesday with Kim pledging to destroy a major North Korean missile facilities and close the country's main nuclear complex, although he said the moves were conditional on U.S. reciprocal action.



Kim renewed promises to work toward the "complete denuclearization of the Korean peninsula" he had made to Moon earlier this year and at his June summit with U.S. President Donald Trump in Singapore.



On Thursday, back in Seoul, Moon said Kim had discussed specific steps he would take toward shutting down his nuclear weapons program for the first time, and expressed hope for a second summit with Trump “in the near future,” with an aim to speed up the denuclearization process.



But while Trump welcomed the developments in Pyongyang, which also included a host of inter-Korean agreements to deepen economic and cultural ties, analysts were mixed, with some seeing the summit as breaking little new ground and others suggesting it might revive nuclear negotiations between Washington and Pyongyang, which have largely faltered since the meeting in Singapore.



Reported by Joonho Kim for RFA’s Korean Service. Translated by Leejin Jun. Written in English by Joshua Lipes.