The United Nations is sending 5,500 additional peacekeepers to South Sudan, where a U.N. official reported thousands of people have likely been killed since fighting began there last week.
The U.N. Security Council approved a measure Tuesday to boost its overall force to nearly 14,000 peacekeepers. U.N. chief Ban Ki-moon said "it may take time" for the troops and police to deploy, and reiterated his call for the country's leaders to resolve their differences through dialogue.
U.S. Secretary of State John Kerry called both President Salva Kiir and former vice president Riek Machar on Tuesday, 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.
The government said that forces loyal to Machar remain in control of Bentiu, one of two state capitals seized by renegade soldiers last week. It said on Tuesday that the army retook the other city, Bor, and was clearing out remaining rebel forces.
The same day, the U.N. human rights office said a mass grave was discovered in Bentiu, the capital of Unity State. Spokeswoman Ravina Shamdasani told VOA that a U.N. official saw 14 bodies in a grave and 20 at a nearby riverside.
She indicated the bodies could be those of some 75 Dinka army soldiers unaccounted for and feared dead.
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Kiir, an ethnic Dinka, has blamed Machar, an ethnic Nuer, of masterminding an alleged coup attempt December 15.
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.
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 President Barack Obama, appealing for an end to the violence.