The president of South Sudan and the leader of the rebellion against him are both calling for dialogue, as the country tries to deal with escalating violence.
Addressing parliament Monday, President Salva Kiir reiterated that he is ready to talk with his opponents as long as there are no preconditions.
Reuters news agency reports that former vice president Riek Machar said dialogue can start "straight away" if the government releases his political allies who were arrested last week.
Machar has been in hiding since President Kiir accused him of leading a coup attempt on December 16. Clashes since then have killed hundreds of people and displaced at least 60,000 others.
Journalist Hannah McNeish, who is in the capital, Juba, told VOA the fighting has a clear ethnic element, with members of the Nuer and Dinka ethnic groups targeting each other.
"There are people going house to house, tracking people down in term of ethnicity. They are taking them out of their houses, they are binding their hands, and executing them if they are not the right ethnicity. This is completely out of control," said McNeish.
For several days, U.N. officials have expressed concern the rift between President Kiir, a Dinka, and Machar, a Nuer, could provoke tribal violence.
U.N. Secretary-General Ban Ki-moon said Monday he was increasingly concerned about the situation in South Sudan.
Soldiers believed to be allied with Machar have taken over the capitals of South Sudan's Unity and Jonglei states.
In an interview with VOA's English to Africa South Sudan army spokesman Philip Aguer said troops will re-take those towns.
"Definitely the army will re-control these areas. It's a matter of days and the army will control Jonglei state and we will work for the re-establishment of the full control of the national army over South Sudan," said Aguer.
The spokesman also accused fighters backing Machar of shooting at a U.S. aircraft that was evacuating citizens from Bor on Saturday. The U.S. military did not identify the shooters, but said four of its personnel were injured.
President Barack Obama said Sunday he "may take further action" to protect Americans in South Sudan.
Obama is on vacation in Hawaii, but he said in a letter to congressional leaders that about 46 U.S. troops were deployed Saturday to help with the evacuation. That is in addition to 45 troops deployed to reinforce the U.S. embassy in Juba.
The U.N. secretary-general called on South Sudan leaders to find a "political means" to address the conflict, saying the continued violence poses a "dangerous threat" to the future of the young country.