Fighting persisted in parts of South Sudan's oil-producing region as African leaders on Thursday tried to advance peace talks between the country's president and his political rivals. The president has accused his rivals of attempting a coup, which he said is what sparked violence now threatening to tear apart the world's newest country.
Kenyan President Uhuru Kenyatta and Ethiopian Prime Minister Hailemariam Desalegn met with South Sudanese President Salva Kiir on Thursday.
A senior government official warned that Riek Machar, the former vice president who now allegedly commands renegade forces in the states of Unity and Upper Nile, had to renounce rebellion before Kiir's government could negotiate with him.
But Michael Makuei Leuth, South Sudan's information minister, said the government has not yet established formal contact with Machar.
"For us, we are not talking with him," Leuth said, referring to Machar, whose whereabouts remain unknown.
Government troops are trying to retake control of Bentiu, the capital of oil-rich Unity state, from Machar loyalists. There was also reported fighting in Malakal, the capital of Upper Nile state, according to Lueth.
The government's petroleum minister Stephen Dhieu Dau reported that rival factions had taken control of some oil wells on Thursday. It was not clear how many they had seized, or whether they had been damaged.
Upper Nile and Unity comprise the country's key oil-producing region, raising fears unrest there could cut off the country's economic lifeblood. South Sudan gets nearly 99 percent of its government budget from oil revenues.
Col. Philip Aguer, the country’s military spokesman, said government troops were "preparing to retake Bentiu as soon as possible" and that pro-Machar forces controlled only "half" of Malakal.
World leaders have urged the country's leaders to stop the violence. Thousands are feared killed.
The United States, Norway and Ethiopia are leading efforts to open peace talks between Kiir and his political rivals.
In a statement published on the Chinese Foreign Ministry website on Thursday, Foreign Minister Wang Yi said China will soon dispatch a special envoy to South Sudan to make contact with all sides.
Pope Francis also urged peace.
Kiir said in a Christmas address that he is willing to open a dialogue with all his opponents.
The United Nations is investigating reports of mass killings since violence began spreading across South Sudan on Dec. 15. The unrest is pitting soldiers from Kiir's Dinka ethnic group against those from the Nuer ethnic group of Machar. South Sudan's top U.N. humanitarian official, Toby Lanzer, said on Monday that he believes the death toll has surpassed 1,000.
Although the capital city of Juba is now calm, fighting appears to be spreading across the country, stretching the limits of humanitarian workers and aid agencies.
The U.N. humanitarian office said aid agencies need $166 million to save lives amid continuing violence.
"The resources will be used to provide clean water and sanitation, health care, shelter, and deliver food and livelihood assistance," the office said in a statement. "It will also ensure that the rights of vulnerable people, including survivors of violence, are better protected. The money will be used to manage sites for displaced people and transport aid workers and supplies to strategic locations where communities are most at risk."
Some 58,000 people have taken refuge in and around U.N. bases in the country and more than 92,000 have fled their homes as a result of fighting that has raised fears of a civil war in the country, according to the United Nations.
South Sudan peacefully broke away from Sudan in 2011 following a 2005 peace deal. Before that, the south fought decades of war with Sudan. The country, one of the world's least developed, still has pockets of rebel resistance and sees cyclical, tribal clashes that result in hundreds of deaths.
Al Jazeera and wire services