WASHINGTON -- New satellite imagery offers further insight into North Korea's prison camps where tens of thousands of prisoners are subject to brutal and inhumane conditions, a US-based group said Thursday.

The 20 new images are published in a report released the same day by the Committee for Human Rights in North Korea, a leading nongovernmental organization tasked with raising awareness of human rights abuses in the North.

The report, "The Parallel Gulag: North Korea's 'An-jeon-bu' Prison Camps," especially sheds light on the prisons and prison camps run by the North's Ministry of People's Security. The other system of political imprisonment is operated by the Ministry of State Security.

The committee said it identified through the satellite imagery tell-tale characteristics of prison camps, such as security enclosures with gated high walls and barbed wire fences, guard towers, dormitories, and workshops or mines located within or adjacent to the prisons.

"The practices documented in 'Parallel Gulag' reveal yet another layer of North Korea's brutal system in blatant contradiction to international laws, including treaties that North Korea has ratified," said David Hawk, the author of the report and a human rights specialist.

Michael Kirby, who chaired the UN Commission of Inquiry on human rights violations in North Korea, said the report updates the record and "shows that North Korea's system of political oppression remains in place as an affront to the conscience of humanity."

"These revelations suggest the imposition of degrees of suffering even more pervasive than the UN COI described in 2014," he wrote in his foreword.

The COI accused North Korea of "systematic, widespread and gross human rights violations." It also called on the regime and the international community to ensure the prison camps are dismantled and the prisoners released without further delay. (Yonhap)