Armed Nuer tribesmen have killed at least 139 members of a rival tribe in an attack in a remote area of southern Sudan, an official has said.
The Nuer gunmen attacked Dinka cattle herders on Saturday in Tonj East, one of the most remote parts of oil-producing south Sudan, and seized about 5,000 animals, the deputy governor of the surrounding Warrap state, Sabino Makana said.
A surge of tribal violence last year resulted in the deaths of about 2,500 people and forced 350,000 to flee their homes in the south, a report issued by ten aid groups including Oxfam, Save the Children and TearFund said.
There was now a risk the violence could escalate, undermining a fragile 2005 peace deal that ended more than two decades of north-south civil war, the report added.
Southern leaders last year accused Khartoum of backing militias to undermine the south, although some politicians acknowledged southern officials may also have been arming fellow tribesmen to build up support ahead of elections due in April.
The UN said it was sending a team to the Tonj East area to check on the reports, saying other sources had confirmed there were a large number of deaths.
Head of the UN's Office for the Coordination of Humanitarian Affairs Lise Grande said fighting had also been reported in three other areas.
The report from the ten aid agencies called on UN peacekeepers to step-up protection of civilians and urged donors to increase funding for development programmes.
The north-south war, which began in 1983, killed around 2m people and drove 4m from their homes, destabilising much of east Africa.
