Atrocities committed in June in Sudan's Southern Kordofan state by armies of the north and south "could amount to crimes against humanity or war crimes," according to a report by the UN human rights agency.
The 12-page report, released on Monday in Geneva, covers the period from June 5 to June 30 and describes a wide range of alleged violations of international law in the town of Kadugli.
The violations are also said to have occurred in the surrounding Nuba mountains, after fighting broke out in Kadugli on 5 June between the Sudanese Armed Forces (SAF) and the Sudan People's Liberation Army North (SPLA-N).
Reported violations included "extrajudicial killings, arbitrary arrests and illegal detention, enforced disappearances, attacks against civilians, looting of civilian homes and destruction of property," as well as massive displacement.
The report describes a number of specific individual detentions and disappearances, including those of women and children.
It says "a series of extrajudicial killings targeted people who were affiliated with the SPLA-N and SPLM, most of whom allegedly were from the Nuba communities".
Navi Pillay, the UN High Commissioner for Human Rights, said despite limited access by investagators to areas affected, what happened in Southern Kordofan was "serious".
"This is a preliminary report produced under very challenging circumstances and with very limited access to affected areas," she said.
"However, what it suggests has been happening in Southern Kordofan is so serious that it is essential there is an independent, thorough and objective inquiry with the aim of holding perpetrators to account."
Pillay expressed concern about continuing violence in the six weeks since the end of the period covered by the report, and noted some of its key recommendations concerning access.
'Shot in public view'
One victim was reportedly shot "in full public view" at the Kadugli Police Hospital, where he had gone to look for his three missing children, it adds.
Another SPLM member, who was working as a contractor for the UN mission in Sudan (UNMIS), "was pulled out of a vehicle by [the] SAF in front of Kadugli Sector IV compound in the presence of several witnesses. Later he was discovered dead ..."
Prepared jointly by the office of the UN High Commissioner for Human Rights and the UNMIS, the report also describes aerial bombardments on civilian areas in Kadugli and elsewhere in Southern Kordofan, adding that they have resulted in "significant loss of life".
"The SAF regularly conducted aerial bombardments in the Nuba Mountains, and in several towns and villages populated by the Nuba," the report adds.
Among the specific bombing incidents cited were SAF airstrikes on airstrips used by humanitarian organisations, the report notes.
Both the SAF and the SPLA-N are reported to have laid anti-personnel mines in Kadugli town, according to the report.
It also describes looting by elements of the Popular Defence Force, an armed group allied with the SAF, as well as alleged attacks on churches, the burning of houses in Nuba villages and interference with medical and humanitarian assistance.
The report also talks of several mass graves in Kadugli itself and in a number of villages in the region.
But the existence of the mass graves and other reports suggesting possible use of chemical weapons have yet to be verified.
Most of the violations and allegations detailed in the report are attributed to the SAF, the Central Reserve Police or their armed allies.
There was no immediate reaction to the report from the armies of the north and south.
Sudan split into two nations in July following a referendum in January by the south to secede from the north after decades of a civil war that claimed millions of lives.
In the run-up to the south's declaration of independence, fighting ensued between the armies of the north and south over the disputed region of Abyei and oil-producing Kordofan.