Editor's Note: (The CNN Freedom Project wants to amplify the voices of the victims of modern-day slavery, highlight success stories and help unravel the tangle of criminal enterprises trading in human life.)
Seoul(CNN) Rim Il arrived in Kuwait in the dead of night, full of high hopes.
It was 1996, during the height of North Korea's famine and chronic food shortage, a crisis that lasted four years and may have cost the reclusive nation as many as three millions lives.
A carpenter by trade, he planned to send the US$120 monthly salary he'd been promised back to North Korea to support his starving family.
He was grateful for the opportunity to earn a living abroad given the hardships at home. He and his fellow workers were given three meals, which included bread, milk, eggs and beef -- things you only dreamed about in North Korea.
But before long Rim's illusion was shattered.
"I worked for five months but I wasn't paid even once," he said.
Rim said he and his fellow North Koreans worked long days toiling on a construction site with little break in between shifts. Living in an abandoned school under tight security, he said they were forced to watch a documentary about then-leader Kim Jong Il during their only night off.
He said he felt like a slave.
"I never even knew I had a passport until we arrived in Kuwait," he said. "The minders gave it to me at immigration then took it straight back. I never even had the chance to open it."
Eventually he had enough and managed slip the minders and escape -- he claimed asylum at the South Korean Embassy in Kuwait.
Rim's experience is one of 13 accounts that NK Watch, a North Korean human rights group based in Seoul, collected as part of its petition against what they call "modern day slavery." All the accounts had a number of things in common -- up to 18 hours of work each day, little or no pay, no freedom and harsh living conditions.
About 100,000 North Korean workers are believed to be working abroad, according to an estimate by a South Korean government official who asked not to be identified. NK Watch believes workers have been sent to more than 40 different countries -- few ever see any money.
Like most of North Korea's cash, it's believed to be diverted to the regime's military and nuclear program, as well as to its elite inner circle.
Kim Kwang Jin, a former North Korean financier, told CNN he once helped this process by funneling money back to the North while working at an insurance company in Singapore that acted as a front for the department that funds projects for the Kim dynasty.
"I managed Kim Jong Il's loyal funds for building palaces and building roads. I received those funds every month and I kept statements of those funds," Kim, who now lives in Seoul, told CNN.
He says it's still happening under current leader, Kim Jong Un.
"If each worker is contributing at least $100 per month, it is a really large amount. Several hundred million US dollars every year (are) flowing into Kim Jong Un's coffers for his nuclear and missile programs."
But with tighter scrutiny by the international community after recent nuclear and rocket tests, North Korea has not been able to generate income from its illegal activities, including smuggling narcotics and weapons, the head of NK Watch told CNN.
"So now these funds are being used for Kim Jong Un's secret fund and nationwide construction projects like the ski resort and water park," said Ahn Myeong-chul, the group's executive director.
"This form of exploitation existed in the past, but it doubled or even tripled since Kim Jong Un stepped in," Ahn added.
READ: Defector says Kim's days are numbered
Ahn filed a petition to the United Nations special rapporteur on slavery last March in Geneva that highlighted the issue of labor exploitation. The petition included the 13 personal testimonies from former North Korean workers.
In an emailed response, the United Nations told CNN that it is currently looking into the allegations and added that they have information the majority of North Korean migrants are being sent to China, Russia and the Middle East.