An estimated 200,000 North Koreans are working overseas under slave-like conditions in a state-sponsored system that has raised up to $3 billion to finance the lifestyles of elites and nuclear development.
That's according to journalists and human rights groups who have uncovered the extent of the network of "exported forced labour" reported to stretch across Asia, Africa, the Middle East and Europe.
This week, an undercover investigation by journalists in China, Russia and Poland exposed secret footage of sites where North Koreans are employed.
One worker speaking anonymously at a construction site in the Russian city of Vladivostok told reporters how they were forced to hand over cash each month as part of their "revolutionary duty".
"You're treated like a dog here and you have to eat dirt. You have to give up being human," he said. "Those who cannot pay it cannot stay here."
In the Polish city of Szczecin, an undercover reporter posing as a recruitment worker visited a shipyard and found around 800 North Koreans employed, mainly as welders and labourers.
A security guard at the site said North Korean workers are "all over" the city.
"They're like us during communism," he told the reporter. "You know why they're not allowed to talk. They could be lured to the West."
The foreman also admitted North Korean employees are there "only to work".
"When there are deadlines, we work without breaks. Not like the Polish. They work eight hours and then go home. We don't. We work as long as we have to."
Site authorities later defended the practice on hidden camera, saying: "If they get anything then that's a good thing.
"They get a glimpse of the world. and they get a few zloty or a few dollars, and this probably helps the entire family."
The companies have denied any wrongdoing and North Korea claims its citizens are working legally. However former North Korean deputy ambassador to the UK Thae Yong-ho told BBC's Panorama the money they send back helps finance the state's nuclear program.
"Where did all that money go?" he said. "It financed the private luxury of the Kim family, the nuclear program and the army. That's a fact."
The Global Slavery Index estimates around one million North Koreans are modern-day slaves with around 200,000 workers serving overseas in 45 countries, mainly in construction, mining and textiles.
Human Trafficking Search said workers generally receive around 10 to 20 per cent of their wages with the rest used as valuable government cash to help get around banking restrictions.
It comes as North Korea has suddenly moved to open up the regime following escalating military tension throughout 2017.
On Wednesday, it emerged CIA director Mike Pompeo recently visited the country ahead of a meeting with US President Trump due to take place this year. North and South Korean leaders are also preparing for a historic summit on April 27.
UN Human Rights Council special rapporteur on North Korea Tomás Ojea Quintana said the "particularly tense" round of missile testing in 2017 had a negative impact on human rights in the country with delays for chemotherapy products and banking transactions that made aid harder to administer.
His recent report said that despite the Winter Olympics providing momentum towards co-operation, the country is still rife with human rights abuses, torture, food insecurity and harsh restrictions on personal freedom.
One woman who tried to escape to China but was repatriated and detained said conditions were "inhumane".
"We were treated like animals, given only corn to eat, or a poorly made soup of dried radish greens. The toilet is located inside a room that hosted a dozen people. You're not allowed to move and you have to sit still in the same position. If you move, they beat you, she said.
The UN estimates 41 per cent of the population — around 10.5 million people — are undernourished.