UN rights chief calls for release of hundreds abducted and abused in South Sudan.

Hundreds of civilians who were taken by opposition forces in South Sudan's Western Equatoria region during an uptick in fighting are still missing, the UN's top rights official said on Thursday, in a call for their immediate release.

The development reportedly happened in April, ahead of the signing in August of a new peace agreement aimed at ending years of bloody civil war involving President Salva Kiir and former vice-President, Riek Machar, who has backing from the Sudan People's Liberation Army in-Opposition (SPLA-IO).

'Most of the abducted civilians are, as far as we know, still being held captive', said Michelle Bachelet, UN High Commissioner for Human Rights. 'The SPLA-IO (RM) must immediately release them, first and foremost the children.'

The High Commissioner's appeal follows the publication of a UN report into grave rights abuses against villagers in South Sudan's Gbudue and Tambura states, both of which are in Western Equatoria region.

It details testimonies from victims and witnesses that indicate how women and girls as young as 12 were abducted by opposition forces...then paraded and lined up for commanders to choose as 'wives'.

Some 900 people were abducted in total and 24,000 were forced to flee their homes, the report notes. Those who were not chosen were left for other fighters who subjected them to repeated rapes, while abducted young men and boys were forced to fight, or work as porters.

At least 28 villages were attacked by the same troops, along with a settlement for internally displaced people and a refugee camp, according to the report, which was compiled jointly by the Office of the High Commissioner for Human Rights (OHCHR) and the UN peacekeeping mission in South Sudan, UNMISS.

During these attacks, victims were...