Last week, Mr. Kiir accused his former vice president, Riek Machar, of attempting a coup. Mr. Machar, whom Mr. Kiir summarily dismissed in July, has denied the accusation and says he will sit down at the negotiating table only after his political allies have been freed from detention.

The battle for the city of Malakal, in the northern part of the country, was particularly fierce on Wednesday. Since Tuesday, 40 people have been treated for gunshot wounds at the hospital there, including five who have died, said Michael White, who is in charge of the Doctors Without Borders mission in South Sudan.

The sound of tanks and rocket-propelled grenades echoed through the streets of the city on Wednesday. Some reports said that Malakal had fallen to the rebels, but a military spokesman said its fate was still undecided. “It’s not clear who controls the city,” said the spokesman, Col. Philip Aguer.

In Bentiu, the capital of the oil-producing Unity State, 26 patients required surgery as a result of the fighting last week. The most serious wounds were inflicted by opportunistic looters wielding machetes in the Bentiu market, Mr. White said. The city is in the hands of a general who sides with Mr. Machar.

Image Credit... The New York Times

“Bentiu is still under control of forces loyal to Machar,” Colonel Aguer said. “For Bentiu, the S.P.L.A. is now studying what to do about it, what action to take.” The S.P.L.A. is the South Sudanese military, known as the Sudan People’s Liberation Army.