SEOUL – The North Korean authorities have distributed high -performance radio signal detectors with high performance border security agents as part of an intensified campaign to prevent residents from making unauthorized telephone calls in South Korea, local sources in RFA told RFA.
A source from the northern province of Pyongan, speaking on condition of anonymity for security reasons, said that agents of the Ministry of State Security in Uiju county near the border with China received the new aircraft last week.
“These portable detectors are designed to find North Koreans who use Chinese mobile phones to contact family members in South Korea,” said the source.
The brand labels of the devices have been removed and the country of origin is not clear, but the source described them as “high performance tools with a wide detection range and a quick signal capture”.
Although smartphones are available in North Korea, the government maintains strict national surveillance by operating a national intranet and keeping the national and international telephone networks completely separated. For ordinary citizens, taking an international call is almost impossible.
Legal international calls must go through operators monitored by the government, allowing authorities to listen easily. Another exception is Yanggakdo International Hotel in Pyongyang, where direct international numbering is authorized, but only for foreigners and elite officials.
Due to these restrictions, many North Koreans are unable to contact relatives who live abroad or who have defected. In desperation, some residents of border regions pay high costs to brokers to use Chinese mobile networks, generally hiding in mountainous areas to avoid detection.
But these calls are risky. Those captured by making unauthorized international calls face severe sanctions, including accusations of betrayal and imprisonment in the work camps.
Border security
Since the supreme chief Kim Jong One has come to power, North Korea has increased border security, an important of major German manufacturing radio signals to block the influx of external information and prevent the leaks of new internal, said the source.
Theoretically, radio signal detectors can identify the source of unauthorized communications by drawing electromagnetic waves issued during telephone calls. Once a signal is detected, security agents can triangulate the location and follow the user.
In response to government surveillance, many residents have used the climbing of hills or to hide in remote mountainous areas to make calls via Chinese mobile networks. New detection devices could make these calls increasingly risky.
The sources that have spoken to the FRG have heard of new portable border guards and say that devices are a major upgrade both speed and upmarket.
“These are not the same detectors used in previous years,” said the northern source of Pyongan. “They can identify the origin of a call much faster and in a larger area.”
“New portable detectors can be used during the move, and that has very worried people,” added the source.
A second source in the province said that surveillance along the border has intensified, in particular from the Pandemic COVID-19, when North Korea closed travel and cross-border trade.
“Security cameras have been installed throughout the border area. Residents claim that surveillance is tighter than ever,” said the source.
The source added that the authorities are particularly aimed at telephone calls with relatives who have resettled in South Korea.
“Anyone who was surprised talking about family rice prices in the South is labeled a spy,” said the source. “The old detection systems could not always resume these calls because of their limited scope.”
Anti-state crimes
Acts such as defection, smuggling or the flight of internal information to the outside world are classified as anti-state crimes in North Korea.
According to a 2024 report from the Korea Institute of National Unification, a reflection group funded by the South Korean government, the North Korean authorities are strictly monitoring and severely punish the possession and use of Chinese mobile phones, generally condemning delinquents to reform by work or detention in labor training camps. The report also notes that in some cases, people who used Chinese phones to contact South Korea were classified as political criminals and imprisoned in political prison camps.
The sources have told RFA that the government had distributed new portable detectors to state security officials in large border areas, including the city of Sinuiju, which is opposite the Chinese city of Dandong, the main conductor of Chinese-North stores.
“Simple clothing agents now patrol the residential districts and wooded hills before dawn, transporting the devices in their pockets to search for illegal telephone signals,” said the second source.
Previously, the authorities could only detect unauthorized calls that lasted more than five minutes. New portable detectors can identify as short as a minute, added the source.
Additional report by Jaewoo Park. Published by Sungwon Yang and Mat Pennington.