U.S. Ambassador to the United Nations Samantha Power is calling on the international community to sanction those in South Sudan who are targeting civilians or acting as "political spoilers."
Power joined an urgent U.N. Security Council meeting Wednesday on the situation in South Sudan. The diplomats viewed what Power called "horrific pictures" of a massacre last week in the town of Bentiu.
The U.N. Mission in South Sudan says rebels killed hundreds of people based on their nationality or ethnic origin after seizing control of Bentiu on April 15. Rebel spokesmen have denied carrying out the killings.
Power said on Twitter late Wednesday that the latest violence in South Sudan has brought the country to a "turning point" and that its government is inciting violence against peacekeepers.
France's U.N. Ambassador Gerard Araud also said council members are considering taking action, writing on Twitter that France supports sanctions against those violating human rights. He said both sides in South Sudan's conflict are using a military approach and that there is no safe place for refugees.
The United Nations has nearly 8,500 peacekeepers in the country. It reported a "deadly and unprovoked" attack on its base in Bor last week by an armed mob that forced its way onto the compound and opened fire on civilians taking shelter.
U.N. peacekeeping chief Herve Ladsous said Wednesday that neither the South Sudan government nor rebels have shown real interest in taking part in peace talks to defuse the crisis that erupted in December. He also faults the government for not adequately protecting its people.
"The United Nations is doing everything it can to protect the civilians that are fleeing the violence, the war. But let us never forget that the primary responsibility for protecting civilians is with the government. We are there to support but it is the government of South Sudan to make it so that its citizens are not killed," said Ladsous.
He said the cycle of violence in South Sudan has to stop.
Ethnic violence and clashes between rebel and government forces in South Sudan have killed thousands of people in recent months. The U.N. refugee agency says the fighting has driven more than 1.1 million people from their homes.
Peace talks in Ethiopia have made little progress.