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(Image: GETTY)

Mysterious random numbers were announced on a chilling state-run radio show last night.

Pyongyang Radio addressed “members of the remote education university” in the broadcast at 12am local time.

The message was believed to be instructions to North Korean sleeper cells undercover in foreign countries.

It is understood spies living abroad are able to understand the code and act on the instructions.

A similar message was aired on March 24 – just days before Kim Jong-un fired a missile into the Sea of Japan.

The message comes amid claims North Korea will detonate another nuclear bomb within 15 days.

In the programme, the announcer said: “From now on, we announce tasks of mechanical engineering review for the Unit 21 expedition members of the remote education university.

"Number 69 on page 602, number 79 on page 133, number 18 on page 216.”

(Image: GETTY)

It is the 31st encrypted broadcast since June 24 last year.

North Korea regularly used book ciphers to communicate with spooks in South Korea during the Cold War.

Pyongyang halted the broadcasts in 2000 as relations with the South thawed.

But leader Kim Jong-un appears to have resumed the practice.