Thousands of civilians have fled a state capital in South Sudan, amid fears of new clashes between rebels and government soldiers.
U.N. humanitarian official Toby Lanzer visited Bentiu on Thursday. In a series of Twitter messages, he said he saw "virtually no civilians" in the center of town, and that shops in Bentiu's main market have been looted and largely destroyed.
Reports from the area say army troops loyal to President Salva Kiir are advancing toward the town, which has been held for several weeks by rebels who support the president's rival, Riek Machar.
Peace talks between the sides in Ethiopia remained at an impasse, with the government again refusing to release 11 political detainees, as demanded by the rebels.
A rebel spokesman at the Addis Ababa talks used the stalemate Thursday to accuse Ugandan forces and gunships of attacking rebel positions. However, Uganda claims its military presence in South Sudan is limited to protecting its stranded countrymen.
For his part, the lead Sudanese government negotiator dismissed the rebel claims of Ugandan aerial attacks as "hostile propaganda."
In remarks to the U.S. Senate Foreign Relations Committee, the top U.S. diplomat for Africa, Linda Thomas-Greenfield, said the U.S. is strongly urging a peaceful resolution to the conflict.
"This crisis will not be solved on the battlefield, and we have made that point over and over again," she said. "Although fighting started less than one month ago, the roots of this conflict are much deeper, and resolution can only come from immediate dialogue between the two sides and a broader reconciliation."
A senior United Nations official warned Thursday that the death toll from recent fighting in South Sudan is likely to be “very substantially” in excess of the 1,000 deaths confirmed so far. U.N. peacekeeping chief Hervé Ladsous told reporters that some 250,000 people in South Sudan have been displaced from the deadly fighting that erupted between rival political factions last month.
“As to the victims, so far we are not able to provide a final figure, but we do know that it will be very substantially in excess of the figure of 1,000 that we know for sure about,” he said.
Ladsous told reporters after briefing the U.N. Security Council that the additional 5,500 peacekeepers authorized by the council last month have begun arriving from other U.N. missions and should all be in place and operational within the next four to eight weeks.
“The priorities now for the U.N. are very clearly in this situation -- to focus on protection of civilians, on human rights, and on helping our humanitarian colleagues to access those populations in need,” he said.
The United Nations says more than 60,000 are sheltering on U.N. bases throughout the country, including 8,000 in Bentiu.
On Thursday, U.N. Emergency Relief Coordinator Valerie Amos said the U.N. is releasing $15 million to support relief efforts in South Sudan. She said U.N. agencies will use the funds to improve living conditions of people stuck in overcrowded camps.
South Sudan's unrest began December 15 with fighting at an army headquarters in the capital, Juba. President Kiir accused his former vice president, Machar, of a coup attempt.
Many soldiers aligned themselves with Machar and seized control of Bentiu and the Jonglei state capital, Bor. Heavy fighting has been reported this week in several parts of the country.
Witnesses say the recent violence has an ethnic component, with targeted attacks between supporters of Kiir, from the Dinka tribe, and Machar, who is from the Nuer community.
(VOA U.N. correspondent Margaret Besheer contributed to this report.)