The increasingly informal nature of North Korea’s economy is making Pyongyang’s illicit international activities harder to monitor, a report published on Tuesday says.

The report, which was titled “Illicit: North Korea’s Evolving Operations to Earn Hard Currency“ and published by the Washington D.C.-based Committee for Human Rights in North Korea (HRNK), examined the ways in which the North Korean regime continues to obtain hard currency, and how the country has adapted to international responses to its activities over the past decades.

But while North Korean officials have been suspected of engaging in illicit cash-generation activities for decades, the report