New surveys show North Korea escapees believe the communist state’s penal system has evolved into a mechanism for extorting money from citizens trading in private markets.

The Washington Post quoted the surveys conducted by the East-West Center on more than 16-hundred North Korean escapees residing in South Korea and China. The center is a research organization established by the U.S. Congress to promote understanding of Asia.

The paper quoted the research center as saying that North Korea has criminalized everyday market behavior and created a new kind of gulag for those it deems economic criminals in reaction to an explosive rise in market activity.

Eighty-five of the surveyed said they were required to pay bribes to engage in market activity, and two-thirds of the surveyed said they had spent a month in labor camps after being caught by security officials.