The United Nations said on Monday (21.04.2014) that rebel gunmen killed "hundreds" of civilians when they retook the oil town of Bentiu last week. "More than 200 civilians were reportedly killed and over 400 wounded at the mosque," the UN peacekeeping mission in South Sudan (UNMISS) said in a statement.

Radio broadcasts had urged fighters to massacre a rival tribe sheltering at a church, mosque and a hospital.

Earlier the UN said it had reports of "targeted killings based on ethnicity" with several dozen corpses rotting in the streets.

Bentiu, capital of Unity state, was recaptured by rebels loyal to sacked vice president Riek Marchar on Tuesday (15.04.2014)

Army unable to contact troops

South Sudan's army said on Saturday (19.04.2014) they had "lost communication" with commanders battling rebels in Unity state.

The army's headquarters in the South Sudanese capital Juba said they have not been able to get through to troops fighting on the ground since Thursday.

James Gadet Dak, a spokesman for Machar, said the rebels were aiming to starve the government of funds for its war chest by seizing oil fields and towns with oil installations.

Over a million people have fled their home since the start of the fighting in mid-December

Meanwhile South Sudan army spokesman Malaak Ayuen said the situation was "all calm" in the flashpoint town of Bor, capital of Jonglei state, where gunmen stormed a UN peacekeeping base killing at least 48 people, including women and children, who were sheltering there.

The UN Security Council called the attack on the camp "an outrage" that may "constitute a war crime."

The top UN official in the war-torn nation, Toby Lanzer, praised peacekeepers for preventing what could have been a massacre of up to 5,000 people and vowed the world body would use "lethal force" again to keep civilians under their protection from harm.

One million at risk from famine

The conflict in South Sudan, which only won independence from Sudan in 2011 and is the world's youngest nation, has left thousands dead and forced around a million people to flee their homes.

The International Crisis Group says the conflict risks tearing the country apart

The fighting has been marked by reports and allegations of atrocities by both sides, with ethnic massacres, child soldier recruitment and patients raped and murdered in hospitals by attacking forces.

A cessation of hostilities agreement signed on January 23, 2014 had largely held until early April, except for isolated skirmishes.

The surge in fighting in the four-month-long conflict comes amid warnings by UN Secretary General Ban Ki-moon that more than one million people are at risk of famine in the war-torn country.

Toby Lanzer told DW that the violence in Jonglei, Unity and Upper Nile states was stopping people from working in the fields in the planting season. "If we miss the planting season, it doesn't take much imagination to conjure up a picture of the suffering and extreme food insecurity that will have been reached by the end of the year," he said.

Analysts are becoming increasingly pessimistic about the future of South Sudan. "Propping up the government in Juba and polishing its legitimacy with a dose of political dialogue and a dash of power sharing will not end the conflict," the International Crisis Group observed in a recent report.