North Korea’s state radio has restarted coded radio broadcasts to the South by transmitting strings of indecipherable numbers, Seoul officials said Tuesday. It is the Cold War-era method of sending coded messages to spies operating in South Korea.
The broadcast lasted 12 minutes from 00.45 a.m. local time on Friday, according to the Yonhap news agency. A female voice announced in the transmission: "Starting now, I will give an assignment to exploration agent No. 27. On page 459, number 35, on page 913, number 55, on page 135, number 86, on page 257, number 2."
Earlier a female announcer at the radio station read numbers for 2 minutes on June 24, according to Seoul’s Unification Ministry and National Intelligence Service.
The broadcasts are similar to North Korea's Cold War method for contacting spies in South Korea. During the Cold War, Pyongyang sent such numbers via shortwave radio to give missions to agents dispatched to South Korea, according to captured North Korean spies.
Such method of communication stopped after the holding of a first inter-Korean summit. The last such broadcasts by the North were made in 2000. Also Pyongyang started give instruction for its spies overseas via the internet.
While South Korea jams most radio frequencies from the North, shortwave signals - such as that used by Pyongyang-based Voice of Korea - are particularly difficult to jam.
South Korean intelligence authorities are trying to work those messages out, but they are now on alert for "possible provocations". Some experts in Seoul view the messages as a North Korean attempt to wage psychological warfare.
Yoo Dongryul, head of the Seoul-based Korea Institute of Liberal Democracy, said the North may be trying to deceive South Korean intelligence officials into believing it’s moving to increase its espionage operations.
He said it’s unlikely the North would rely on old-fashioned “number stations” broadcasts, whose hard-to-reset coding patterns had already been exposed to South Korean intelligence officers. He said North Korea currently uses a more sophisticated espionage communication method known as steganography, in which secret messages are hidden within audio and video files.