South Sudan's former vice president has called for the overthrow of President Salva Kiir, as tension and violence continue to rise in Africa's newest country.
Riek Machar told Radio France Internationale on Thursday that he would like to see a "palace revolution" in which the South Sudanese army topples the head of state.
Mr. Kiir had accused Machar of launching a coup attempt this week with an attack on army headquarters in the capital, Juba. That fighting set off violence that the government says has killed about 500 people and wounded 700 others since Sunday.
Thursday, the government said rebelling soldiers had seized control of Bor, a town north of Juba.
The government insisted it has control of the capital. But the United Nations reported some unrest, saying people at Juba University and another part of the city have requested protection by U.N. peacekeepers.
Also, U.N. deputy spokesman Farhan Haq said youth from the Nuer ethnic group had forcibly entered a U.N. base in Jonglei state where a group of civilians had taken refuge.
"Fighting took place and we have yet to ascertain the situation. We fear there may have been some fatalities but can not confirm who and how many at this stage."
Observers have raised concerns that a rift between Machar, a Nuer, and Mr. Kiir, a Dinka, could worsen already-chronic tribal violence in South Sudan.
In a VOA interview, Human Rights Watch Africa analyst Leslie Lefkow said South Sudanese soldiers may have specifically targeted people from the Nuer ethnic group during this week's fighting in Juba.
"We have spoken to a lot of people in Juba who were witnesses of what has been happening over the last few days and people have told us really horrifying accounts of civilians - men, women and children - who were in their houses, in their compounds, hiding from the fighting, and who were actively sought out by soldiers coming into their homes, shooting them, often asking people whether they were Dinka or Nuer."
Human Rights Watch also said there are reports that Nuer soldiers had targeted ethnic Dinkas.
The government denied there was an ethnic element to what it describes as Machar's "aborted coup."
In another development, top ministers from the regional Intergovernmental Authority on Development group are traveling to South Sudan on a peace mission.
The group was instrumental in mediating a 2005 agreement that ended Sudan's civil war with what was then its southern region.
President Kiir said Wednesday he is willing to hold talks with Machar. U.N. Secretary-General Ban Ki-moon has urged the president to engage with his opponents and cooperate with the United Nations.
Mr. Ban said Wednesday that as many as 20,000 people have taken refuge with the U.N. mission in Juba. ]]