Amnesty International says it has compiled a list of 35 people arbitrarily detained without charge or trial by the National Security Service.
Human rights group says some of the detainees have been held for close to two years, without access to lawyers and with very limited access to their families and the outside world.
It says the list has been published as part of a briefing tittle: “Denied protection of the law: National Security Service detention in Juba, South Sudan”.
It says the detainees include a 65-year-old university professor, a Ugandan aid worker and a journalist employed by Radio Miraya.
“These detainees lack access to adequate food, medical care and sanitary facilities. NSS have also beaten detainees, particularly in the days following their initial arrest,” said Sarah Jackson, Amnesty International’s Deputy Regional Director for East Africa, the Horn and the Great Lakes.
“These detainees and others held without charge must immediately be released, or charged with a recognizable offence before a competent civilian court,” said Sarah Jackson.
Amnesty International says it believes there are other detainees in the National Security headquarters and that the 35 men represent only a small fraction of those currently under arbitrary detention.
“The government should also initiate prompt, effective and impartial investigations into NSS detention practices and limit the agency’s activities to intelligence gathering and analysis,” she added.