The number of political prisoners in North Korea is alleged to have grown to 200-thousand over the past ten years.

Amnesty International said on its Web site that the scale of North Korean political prison camps has been expanded significantly since 2001.

The international human rights organization revealed satellite images of four North Korean political prison camps in a recent online report. The images show the location, size and conditions inside the camps.

Amnesty International also quoted former inmates and guards of the political prison camp at Yodok as saying that prisoners are subjected to forced labor, torture and other inhumane treatment. They added that conditions are close to slavery and public executions still continue inside the camps.

Amnesty International Asia Pacific Director Sam Zarifi urged North Korea to close down the political prisoner camps. He expressed concern that the camps are growing in size as North Korea moves toward an era of new leadership under Kim Jong-Il's third son, Jong-un, and a period of political instability.