NORTH Korea is feeding its construction workers crystal meth to try and speed up completion of a new skyscraper, it has been claimed.

The exhausted workforce is being openly supplied with the drug as their chiefs come under increasing pressure to finish the massive tower.

2 Bosses on the Pyongyang project are opening feeding workers crystal meth, it is claimed

2 Bosses started using the drugs as they came under increasing pressure to finish the new skyscraper - a pet project of Kim Jong-un Credit: Getty Images

This in turn has led to grafitti being daubed across Pyongyang mocking bosses and the industry.

According to Radio Free Asia (RFA), slogans found on a derelict building read "Pyongyang speed is drug speed" and referred to workers as "drug troops".

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The phrases are believed to be mocking slogans used by North Korea's construction industry.

Methamphetamine, also known as "ice" or crystal meth" is an extremely powerful stimulant.

It increases the user's energy levels, alertness and physical activity and can last four hours - making it the ideal slave labour drug.

A source told RFA: "Investigators are warning construction workers that they will be severely punished for further incidents of this kind.

"(They) are undergoing terrible sufferings in their work."

The skyscraper project - a pet project of tyrant Kim Jong-un - has continued late into the night in recent months as bosses draft in thousands of residents to work on it.

North Korea's problem with methamphetamine has been widely reported - the government produces the drug then ships it abroad.

Its annual income from the drug is believed to be hundreds of millions.

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