U.S. and U.N. officials are renewing calls for peace in South Sudan, amid growing ethnic violence and more clashes between the army and rebel soldiers.
The latest fighting is centered in Malakal, capital of oil-rich Upper Nile State. Army spokesman Philip Aguer says clashes between rebels and government loyalists that began Tuesday resumed on Wednesday, with both sides still present in the town.
Meanwhile, more than 40,000 people remain sheltered at U.N. bases, seeking refuge from the fighting or ethnically-motivated violence between the Dinka and the Nuer, South Sudan's two largest tribes.
U.N. humanitarian official Toby Lanzer says it is likely thousands of people have been killed since the unrest began 10 days ago.
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However, the U.N. mission in South Sudan has denied a report that a mass grave was found in Bentiu, the Unity State capital held by rebels.
The U.N. human rights office said Tuesday that the bodies of up to 75 ethnic Dinka soldiers had been found. But the U.N. mission says the report was an "inflation" of a skirmish that resulted in about 15 fatalities.
In a "Christmas Message" to South Sudan, U.S. ambassador Susan Page expressed hope that peace may prevail in the country. U.N. Secretary-General Ban Ki-moon released a video message
, calling on the country's leaders to settle their differences peacefully, and protect civilians from attacks.
On Tuesday, the U.N. Security Council voted to send an additional 5,500 peacekeepers to South Sudan. The deputy commander of the U.N. force in South Sudan, Brigadier General Asit Mistry, said Wednesday that peacekeepers will likely "trickle in" from other African countries.
Earlier, U.S. Secretary of State John Kerry called both President Kiir and his rival, former vice president Riek Machar, urging them to halt the fighting and hold mediated political talks.
Both men have said they are ready for dialogue, but the government rejected Machar's demand that detained opposition leaders be released first.
Kiir, an ethnic Dinka, has accused Machar, an ethnic Nuer, of masterminding a coup attempt in Juba December 15. Machar has not claimed responsibility for a coup but has said the army should remove Kiir from power.
The United States says 150 Marines have been moved to Djibouti, ready to enter South Sudan to evacuate Americans and protect U.S. facilities.
The White House on Tuesday released Dinka- and Nuer-language versions of a recent statement by U.S. President Barack Obama, appealing for an end to the violence.
Members of the South Sudan rebel delegation attend the opening ceremony of South Sudan's peace negotiations, Addis Ababa, Ethiopia, January 4, 2014.
Taban Deng Gai, left, head of the rebel delegation and South Sudan's leader of the government delegation, Nhial Deng Nhial, attend the opening ceremony of South Sudan's peace negotiations, Addis Ababa, Ethiopia, January 4, 2014.
Unidentified members of the delegation from the South Sudan government and western observers meet at the Sheraton Hotel, Addis Ababa, Ethiopia, January 4, 2014.
A displaced mother and her baby, one of the few to have a mosquito net, wake up at a refugee camp, Awerial, South Sudan, Jan. 2, 2014.
A young displaced girl carries a bucket of water back to her makeshift shelter at a United Nations compound. The compound has become home to thousands of people displaced by the recent fighting, Juba, South Sudan, Dec. 31, 2013.
Displaced people gather inside a mosquito net tent as they flee from the fighting between the South Sudanese army and rebels in Bor town, in Juba, South Sudan, Dec. 30, 2013.
A displaced woman hangs up laundry on the plastic sheeting wall of a latrine at a United Nations compound, Juba, South Sudan, Dec. 31, 2013.
Yared, 2, is held by his mother, Madhn, who fled from the town of Bor a few days ago. She receives medicine for her child at a Medecins Sans Frontieres (MSF) medical tent, at a United Nations compound, Juba, South Sudan, Dec. 31, 2013.
A young displaced boy rests on the wheel arch of a water truck while others fill containers from it, at a United Nations compound, Juba, South Africa, Dec. 31, 2013.
A family makes tea outside their makeshift shelter at a United Nations compound, Juba, South Sudan, Dec. 31, 2013.
A general view of a camp for displaced people set up in a United Nations compound in Bor, South Sudan, Dec. 25, 2013.
South Sudan army soldiers hold their weapons as they ride on a truck in Bor, Dec. 25, 2013.