A new effort to tighten borders in the Democratic People’s Republic of Korea to prevent defections has also inadvertently disrupted North Korea’s alleged drug smuggling trade. Sources inside the country revealed that the nationwide crackdown has profoundly affected usage of the once-popular drug, methamphetamine, as domestic drug smugglers and suppliers slow production out of fears of getting caught.

Tightening border patrols of North Korea’s increasingly porous borders was originally aimed at cracking down on defectors, illegal cellphones and other electronics as well as black market smuggling of cultural items from China and South Korea. Now, however, as border patrols ramp up, domestic drug smuggling has gone down. Most of Pyongyang’s crystal meth production has been fueled by demand from China’s border cities in the northeast, where narcotics are illegal and drug smuggling is often punishable by death. While most of the narcotics produced would eventually end up in the hands of Chinese gangs across the border, usage also grew at home. As a result, North Korea’s addicts find themselves embarking on long and sometimes dangerous trips to find a reliable supply.

“Border control has become a lot tighter, making methamphetamine harder to get,” an unnamed female source in Ryanggang province told Daily NK, a South Korea-based news site. “In the past, you could get meth in the provincial black markets, but these days this has become more challenging, so people are seeking out places where it’s [still] being made.”

“Currently, it’s very hard to find anyone in Hyesan [on the Chinese border] who smuggles or sells drugs,” she said. “Some people who use meth will travel to Hamhung and then climb through the mountains on foot to get back to Hyesan”, which, according to the report is a 360-mile journey.

However, she said that even venturing to the source won’t guarantee users a fix: “State Security Department and Ministry of People’s Security officials have figured out that people head to meth-producing cities [to buy drugs] so officials spend a lot of time on the streets.”

Despite widespread reports of North Korea’s drug trafficking and addiction problem, government officials maintain that it does not happen. In 2013, KCNA, North Korea’s state-run news agency and government mouthpiece published an article denying the existence of an illicit drug market.

“The illegal use, trafficking and production of drugs which reduce human beings into mental cripples do not exist in the DPRK,” she said.