Recently Sungwoon Bang escaped from North Korea into South Korea. After his first escape attempt, he was encarcerated by the Chinese:

The prison in China had cameras; so whenever we talked or lay down, the police would come and beat us up with bamboo sticks and electric clubs.

Nice, eh? But nothing compared to North Korea:

Nongpo Concentration Center is the main center for preliminary examination under the Security Service department at North Hamkyung-do. Here, economic migrants and North Koreans who escape to China have their cases examined. While awaiting decisions, they are put to hard labor. At the center, detainees are examined before they are allowed to sleep at night. When they have confessed all, they are allowed to sleep. So, they confess to things they haven't done. One man confessed to stealing a train. It made no sense at all. These terrible examinations meant I couldn't sleep most nights.

And:

I was forced to labor for thirteen to fourteen hours a day. If I didn't complete my tasks in that time, I had to continue until they were complete. The labor was mostly filling blocks with carbide ashes and mud. All the processes were performed by hand. The daily workload for ten people was twenty thousand blocks. To do this, we had to rush all the time, not even having time to use the toilet yet still we couldn't complete our tasks.

One of the worst experiences was trying to sleep at night. Because there was no sanitary facility in the prison, we weren't able to wash our clothes or take showers. When we woke up, we merely washed our faces with water drawn outside. So we were infested with lice, and plagued by bedbugs and fleas. After fighting them all night long, we were too tired even to stand up in the morning. After our severe daytime labors and our nightly examinations by the security police, we would sit on the cold concrete ground of the prison, naked and catching lice and bedbugs. It was like a scene from the movie Auschwitz, about the 2nd World War.

Living in such conditions, nits became like grapes inside our hair. The women seemed to live more terribly than the men. Six people died from unknown illnesses in just two months. A friend who slept by me was found dead one morning.