A senior official in South Sudan said Saturday that government troops will attack the main rebel stronghold if rebels turn down a proposed cease-fire.
The government had offered the truce on Friday to end two weeks of ethnic violence that has killed more than a thousand people.
Those rebel forces are loyal to former Vice President Riek Machar, accused by supporters of President Salva Kiir of leading a coup attempt two weekends ago that sparked violence across the country.
Machar is skeptical of a truce, the BBC reports, saying there must be credible negotiations first.
Fighting continued on Friday as each side sought to dominate an oil-rich region in the north now under the control of forces loyal to Machar. South Sudan gets nearly 99 percent of its government budget from oil.
East African leaders and international powers including the U.S. are urging dialogue between factions on the 2-year-old nation. The United Nations is investigating reports of mass murder and atrocities committed against civilians by soldiers loyal to both men. Tens of thousands of refugees are taking shelter in UN-sponsored camps.
In the northern city of Malakal, people are taking advantage of the momentary lull while tentative negotiations progress. "It was surprisingly calm driving through the street," NPR's Gregory Warner reports.
"People were walking to the Nile with jerrycans on their head, trying to get some water, and they were even bringing their sons and daughters, so they felt comfortable enough," he said. "However, you can see from the kind of busy activity here in the camp that people are not wanting to venture outside tonight, and people just want to bed down and be safe and avoid the bullets."
More fighting is expected. The AP reports, "Twenty-five thousand young men who make up a tribal militia known as the 'White Army' are marching toward a contested state capital in South Sudan, an official said Saturday, dimming hopes for a cease-fire."