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In page Kwalliso:

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Estimates suggest that at the start of 2007, a total of six kwalliso camps were operating within the country. Despite fourteen kwalliso camps originally operating within North Korea, these later merged or were closed following the reallocation of prisoners.[2] Kwalliso gained yet more international attention when Otto Warmbier, an American college student, was jailed in a kwalliso and died very shortly after release.[citation needed]