South Sudan troops outside rebel-held city; militants mingling with refugees, army says

In this photo taken Sunday, Dec. 22, 2013 and released by the United Nations Mission in South Sudan (UNMISS) on Monday, Dec. 23, 2013, displaced people take shelter in the U.N. compound where they get assisted by the World Food Programme (WFP) and UNMISS, in Bentiu, the capital of the oil-producing Unity state, in South Sudan. Civilian helicopters evacuated U.S. citizens from the violent South Sudan city of Bor, capital of Jonglei state, seeing bouts of heavy machine gun fire, but 3,000 citizens from countries like Canada, Britain and Kenya remain trapped there, a top U.N. official said Monday. (AP Photo/UNMISS, Anna Adhikari) (The Associated Press)

In this photo taken Sunday, Dec. 22, 2013 and released by the United Nations Mission in South Sudan (UNMISS) on Monday, Dec. 23, 2013, a food distribution by the World Food Programme (WFP) supported by UNMISS takes place for displaced people taking shelter in the UN compound in Bentiu, the capital of the oil-producing Unity state, in South Sudan. Civilian helicopters evacuated U.S. citizens from the violent South Sudan city of Bor, capital of Jonglei state, seeing bouts of heavy machine gun fire, but 3,000 citizens from countries like Canada, Britain and Kenya remain trapped there, a top U.N. official said Monday. (AP Photo/UNMISS, Anna Adhikari) (The Associated Press)

South Sudan's military spokesman says there is increasing tension at a United Nations camp in the rebel-held city of Bor because armed elements have entered the congested area where the U.N. says about 17,000 civilians are seeking protection.

Col. Philip Aguer said South Sudanese troops are outside Bor and will soon advance on the city. Bor is controlled by troops loyal to the country's former vice president. Aguer said troops will also soon advance on another rebel-held city, Bentiu, in the oil-rich region of Unity state.

The United States and Ethiopia are leading efforts to open peace talks on the 10-day-old crisis. Officials say President Salva Kiir and former Vice President Riek Machar have agreed to meet but specifics including the status of Machar's imprisoned compatriots are holding up talks.