Fugitive former South Sudanese vice president Riek Machar has denied government allegations that he tried to stage a coup at the weekend.
Mr Machar, who fell out with President Salva Kiir in July, accused him of "inciting tribal and ethnic violence" to cover his own failings.
The UN has said the fighting has claimed hundreds of lives, and warned that it could descend into a civil war.
He blamed Sunday's fighting on a conflict between members of the presidential guard, and said it spread across parts of the capital, Juba.
He added that government troops used the incident to arrest some of his supporters on Monday, and that he himself escaped.
"Someone wanted to frame me," he said. "I had to flee. They are hunting me down."
The whereabouts of Mr Machar are unclear. He told the BBC he was still in South Sudan and was "not going to leave the country".
Details of the fighting have been sketchy, but a meeting of the UN Security Council in New York on Tuesday was told that the clashes were "apparently largely along ethnic lines".
French UN ambassador Gerard Araud, who holds the rotating presidency of the Security Council, said up to 20,000 people had taken refuge in the UN mission in Juba.
"Some reports are speaking of hundreds of casualties. For the moment we can't confirm this, but in any case it is a heavy toll," Mr Araud told the BBC.
He said the conflict had "the potential of a civil war" between the two main ethnic groups, the Dinka and the Nuer.
"If you see the people going with Dr Riek [Machar], some are Dinkas, some are Chol, Nuer and other tribes," Said the governor of Unity State, Simon Kun Pouch.
President Kiir has said a group of soldiers supporting Mr Machar had tried to take power by force on Sunday night, but were defeated.
He said the clashes began when uniformed personnel opened fire at a meeting of the governing party, the Sudan People's Liberation Movement (SPLM).
Fighting continued into Monday when the government said it was back in full control.
However, fresh gunfire erupted on Tuesday near the presidential palace and many other areas of Juba.
Information Minister Michael Makuei Lueth said Mr Machar - who leads a dissident faction within the SPLM - was thought to have escaped with some troops.
On Tuesday, the government said former Finance Minister Kosti Manibe, former Justice Minister John Luk Jok and former Interior Minister Gier Chuang Aluong were among 10 opposition figures who had been arrested.
South Sudan has struggled to achieve a stable government since becoming independent from Sudan in 2011.
The independence referendum was intended to end a decade-long conflict, led by the SPLM, against the north.
But the oil-rich country remains ethnically and politically divided, with many armed groups active.
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