The United Nations' special representative on human rights in Sudan has completed an 11-day visit to the country. Among other issues, she raised particular concern with the recent wave of tribal violence in the country's south, urging the semi-autonomous southern government to increase its response.

Speaking in Khartoum at the end of her visit to Sudan, Sima Samar gave particular weight to challenges facing the country's semi-autonomous south.   

"I think all the situation of human rights, the basic rights of the people to life which is affected unfortunately by the tribal clashes and also by the attacks of the LRA and also basic social services is not really very good," she said.

She called on the government of southern Sudan to do more to address the clashes between ethnic groups that have killed hundreds of people this year. Her appeal follows a statement from the U.N. earlier this week that tribal violence in the south has claimed more lives in recent months than the conflict in Sudan's western Darfur region, which has diminished in intensity in recent years.

Tribal violence, much of it related to cattle-raiding has long been common in Southern Sudan.  But Samar says the scale of the violence this year is unusually high, echoing a view expressed last month by south Sudan's president, Salva Kiir.  Samar also noted that the latest wave of clashes has seen more targeting of women and children than in the past.

Sarah Preston, Sudan project coordinator for the organization Safer World, says lack of data makes it difficult to assess whether the scale of violence has indeed been greater than in previous years, but agrees that the character of the attacks have changed.

"What has been particularly alarming about some of the violence that took place this year was the targeting of women and children and civilians in some of the violence, whereas previously many of the clashes were between armed youth and soldiers who are normally associated with cattle raiding as well as the warrior groups," she said.

Samar urged the southern government to increase its troop presence in areas like Jonglei State, where a series of clashes this year between the Nuer and Murle ethnic groups have left over 700 people dead, according to most estimates.  Samar says those responsible for the violence should face justice.

Last month, southern Sudan's president announced an ambitious campaign to disarm civilians throughout southern Sudan.

But Preston, whose organization recently studied a similar effort last year, says civilian disarmament may not be the best approach.

"Until fundamental issues relating to the government's own security provision to civilians begin to be addressed as well as south-south peace-building, disarmament has the potential to be very divisive and actually to make tensions worse because people are unwilling to give up their weapons or are fearful of giving up their weapons if they feel that there isn't other means to defend themselves," she said.

Preston says the southern security efforts continue to be oriented towards the conflict with the north, preventing more attention to security threats within the south.

North and south Sudan fought a two-decade civil war that came to an end with the signing of the Comprehensive Peace Agreement in 2005.  But with the approach of the biggest hurdles involved in that agreement, including national elections scheduled for next year and a referendum on southern independence in 2011, a return to violence is a growing concern.

Samar also highlighted continued human rights challenges in Darfur, where she said humanitarian organizations currently on the ground do not have the capacity to fill the gap left by the expulsion of thirteen international NGOs earlier this year, following the approval of an arrest warrant for Sudan's president by the International Criminal Court.

Samar also raised concerns with press censorship and restrictions on political speech, saying freedom of expression is necessary if the country hopes to hold fair elections next year.

Samar will make a presentation to the UN's Human Rights Council in Geneva on June 16.