Some of the victims "were shot in the bushes" around Juba, the capital, Information Minister Micheal Makuei Lueth told The Associated Press today, citing a report from the minister of defence.
He said up to 700 others had been wounded.
The clashes apparently are pitting soldiers from the majority Dinka tribe of President Salva Kiir against those from ousted Vice President Riek Machar's Nuer ethnic group.
South Sudan has been plagued by ethnic violence since it peacefully broke away from Sudan in 2011 after decades of civil war.
The fighting began Sunday in the capital under circumstances that are still unclear, but the city was mostly calm Wednesday amid a heavy security presence.
South Sudanese military spokesman Col Philip Aguer told the AP there was fighting early Wednesday among troops in Jonglei, the largest state in South Sudan, and he was trying to confirm reports there of desertions from the military. "We are cautiously monitoring the situation," he said. "We don't know who is fighting who."
She said parts of Juba have been reduced to rubble by the fighting of the past few days.
UN diplomats in New York said yesterday that as many as 500 people have been killed in the violence since Sunday but didn't describe how they arrived at that number. Copeland told the AP earlier that she had heard of casualty figures that exceeded 500, but that included both the dead and the wounded.
