SEVEN years ago, David Yau Yau was a theology student at Emmanuel Christian College in the south of Sudan. Today he is the leader of a militia engaged in a bloody battle with the government of the new country there.

Earlier this month, the Primate of the Episcopal Church of Sudan, Dr Daniel Deng, called on this "prodigal son" to return to the negotiating table, as the UN warned that 100,000 civilians in Jonglei had been cut off from aid as a result of fighting.

"We do not wish to accuse nor demonise David Yau Yau," Dr Deng said. "He is our brother, our son, our fellow citizen, our parishioner, loved by us. But we wish to advise him that in the newly independent nation of South Sudan, violence is no longer acceptable as a means of solving disputes."

The government crackdown, launched in March, on the Yau Yau insurgency in Jonglei is taking place amid a resurgence of conflict in the state between the Lou Nuer and Murle groups (Mr Yau Yau belongs to the latter). 

On Monday, the UN announced that it was stepping up its military patrols in the state to allow families to return home and to provide access for humanitarian aid. Since last month, an airlift has been providing food to two previously inaccessible villages.

Dr Deng has suggested that Mr Yau Yau is being supported by a foreign government to destabilise the country, and that some political interests within South Sudan may be manipulating the situation for their own ends. He also said that the Yau Yau rebellion "is not part of the same dynamic as the conflict between communities".

Human Rights Watch has reported that human-rights violations by the army of South Sudan are "cited as a major reason why large numbers of Murle youth joined the rebellion led by Yau Yau".

Last month, the agency claimed that the army had failed to stop armed Lou Nuer youth from moving into Murle areas, and had committed "serious abuses" against civilians. This "reinforces the perception that South Sudan's leaders are taking sides in this ethnic conflict".

Last year, the Presidential Committee for Peace, Reconciliation and Tolerance brokered a peace agreement signed by the leaders of Jonglei's main communities. Last week, Dr Deng, who chaired the committee, complained that the government, the UN, and charities had failed to devote enough attention to its implementation.

Refugee workers ejected. Sudan has not renewed the work permits of20 of the 37 members of the UN High Commission for Refugees (UNHCR), based in Darfur. Most were asked to leave in July. The agency said this month that ithad had to scale down its support for displaced people there. There are currently two million internally displaced persons in Darfur, of whom 1.2 million live in camps.