Gunmen who targeted both children and the elderly left "piles and piles" of bodies — many of those in a mosque — in a provincial capital in South Sudan, the UN's top humanitarian official in the country said Tuesday.



Toby Lanzer told The Associated Press in a phone interview Tuesday that the ethnically targeted killings are "quite possibly a game-changer" for a conflict that has been raging since mid-December and that has exposed longstanding ethnic hostilities. There was also a disturbing echo of Rwanda, which is marking the 20th anniversary this month of its genocide that killed 1 million people.

"It's the first time we're aware of that a local radio station was broadcasting hate messages encouraging people to engage in atrocities," said Lanzer, who was in Bentiu on Sunday and Monday. "And that really accelerates South Sudan's descent into an even more difficult situation from which it needs to extract itself."



UN human rights investigators said late Monday that hundreds of civilians were killed last week because of their ethnicity after rebel forces seized Bentiu, the capital of oil-producing Unity state. Those rebel forces are Nuer, the same ethnic group that former Vice President Riek Machar, who is now a rebel leader, comes from.



Lanzer said thousands of civilians from several ethnic groups are streaming to the UN peacekeeping base in Bentiu because many believe more violence is coming. The base now holds 25,000 people but has only one litre of water per person per day and only one latrine per 350 people.



"The risk of a public health crisis inside our base is enormous," he said.

Severe risk of famine emerges amid crisis

As rebel forces entered Bentiu last week, residents were led to believe that by entering the city mosque they would be safe, Lanzer said, citing accounts from survivors. But once inside they were robbed of their valuables — mostly money and mobile phones — and a short while later gunmen arrived and began killing, both inside the mosque and inside the city hospital.



British Ambassador Ian Hughes on Tuesday said the April 15-16 killings are a clear violation of international law. He said those behind the atrocities and those inciting the killings will be held to account.



UN officials began helping to clear the bodies from the streets and city buildings. Lanzer arrived in Bentiu on the third day of that operation but still counted 150 bodies. He said the UN is documenting the killings and will soon have "a pretty good grasp" on the precise number killed.



The violence is only one part of a dual crisis South Sudan faces. Because of all the fighting, very few residents are tending to their crops. Lanzer said there is a severe risk of famine in coming months because April and May is when people should be planting and cultivating.



The UN hasn't spelled out clearly who exactly the victims were, but because ethnic Nuers carried out the killings it is mostly likely that ethnic Dinkas were among those killed. The UN also said former residents of the Darfur region of Sudan were among those killed in the slaughter. Nuer residents who refused to take part in the attacks were also killed.



The UN has been warning of mounting evidence of ethnically-targeted killings in the world's newest nation as both government troops and rebel forces lose and gain territories in sporadic clashes. Despite a ceasefire signed earlier this year, both sides continue to trade allegations over human rights violations.