Reuters report by James Pearson |
SEOUL
SEOUL (Reuters) - "Now we'll begin a mathematics
review assignment for members of the 27th expeditionary unit of the distance
learning university," the woman's voice crackled over the radio.
"Turn to page 459, question 35; 913, question 55;
135, question 86."
Isolated North Korea has restarted coded radio broadcasts, presumed to be targeted at its spies, for the first time in 16 years last month, South Korea said on Wednesday.
The messages, a recording of which was broadcast by South
Korean TV channel KBS, were disguised as a mathematics lesson for distance
learners and reappeared on North Korean radio station Voice of Korea in the
early hours of Friday.
North and South Korea are still technically at war after
the 1950-53 Korean War ended in a truce, not a peace treaty, and tensions are
running high.
North Korea, which has carried out a string of rocket and
nuclear weapons tests in defiance of UN Security Council resolutions, said on
Wednesday it had conducted a ballistic missile test that simulates strikes
against South Korean ports and airfields used by the U.S. military, apparently
referring to three missile launches on Tuesday.
Those missile launches were seen as a show of force a
week after South Korea and the United States chose a site in the South to
deploy the Terminal High Altitude Area Defence (THAAD) anti-missile system to
counter threats from the North.
FOR YOUR SPIES ONLY
The radio messages, also known as numbers stations, work
by broadcasting strings of seemingly random numbers over shortwave signals to
an agent in the field. The technique, a method of sending one-way secret
messages, dates to the French Resistance in World War Two and is still in use
by some governments today.
South Korea jams most North Korean radio frequencies but
Pyongyang-based Voice of Korea broadcasts on shortwave signals which can be
picked up far beyond the Korean peninsula, and are difficult to jam.
The receiving agent, armed with a radio and a pen, uses
an easily concealed pad with corresponding letters on it to listen to and
decrypt the secret message.
"(North Korean) numbers broadcasts have been on hold for quite some time but have recently resumed, something we think is very regrettable," Jeong Joon-hee, a spokesman for South Korea's unification ministry, told a media briefing on Wednesday.
It was not clear whether the signals were meant to
deceive or deliver genuine instructions.
"I can't speak to their intentions, but we hope that
the North will refrain from an old practice like this and behave in a manner
that's conducive to improving South-North ties," Jeong said.
Seoul has also operated a numbers station, former agents
told Reuters in 2013. Officials at the National Intelligence Service were not
immediately able to confirm their use.
South Korea's station is known as "V-24" to amateur radio enthusiasts who have tracked the source of the signal to a location somewhere south of the Demilitarised Zone separating the two Koreas, and has been known to begin with a scratchy rendition of Beethoven's Piano Sonata No 8.
South Korea : V24 --- XYZ
Korean Numbers Station Enigma Code : V24 Mode : AM
Schedule; ** Broadcasting of about 8 minutes 1300-1308, 1330-1338, 1400-1408, 1430-1438, 1500-1508, 1530-1538 Frequency: 4900, 5290, 5715, 5900, 6215, 6310 kHz (irregularly)
A snippet of the numbers transmission was aired by KBS TV http://www.yonhapnewstv.co.kr/MYH20160719015700038/
