South Sudan rebels take Bor town after 'coup attempt'
South Sudanese rebels have taken over a key town, the military has said, as fighting continues after Sunday's reported coup attempt.
"Our soldiers have lost control of Bor to the force of Riek Machar," said army spokesman Philip Aguer.
President Salva Kiir has accused Mr Machar, the former vice-president, of plotting a coup - a claim he denies.
The unrest, which began in the capital Juba, has killed some 500 people and sparked fears of widespread conflict.
While acknowledging that forces loyal to Riek Machar had taken control of Bor, the army also said Maj-Gen Peter Gadet Yak had mutinied, taking with him some troops.
What is not clear is if troops loyal to Mr Machar are working together with those of Maj-Gen Gadet, or if in fact they are the same soldiers.
But it is likely, because of the history of relations between the two, and because of their background. They are both Nuers, while President Salva Kiir is Dinka.
If the two are indeed in control of Jonglei, it is possible that they might try to overrun the neighbouring oil-producing states of Unity and Upper Nile.
This will mean the oil-reliant economy could come under their control.
Since independence from Sudan, several rebel groups have taken up arms and one of these is said to have been involved in the capture of Bor.
The United Nations has expressed concern about a possible civil war between the country's two main ethnic groups, the Dinka of Mr Kiir and the Nuer of Mr Machar.
In an interview with Radio France Internationale, Mr Machar called on the army to remove the president.
"We want him to leave, that's it," he told the station.
Mr Machar was sacked by Mr Kiir in July.
The UN has called for political dialogue to end the crisis, and the Ugandan government says its president has been asked by the UN to mediate between the two sides.
A delegation of East African foreign ministers has arrived in Juba to try to mediate in the crisis.
The UN peacekeeping mission says it is sheltering civilians in five state capitals, including Juba, Bor and Bentiu, the main town of the oil-producing state of Unity.
Britain and the US have both sent planes to airlift their nationals out of the country, and a US defence official described the situation as "getting ugly".
Bor is the capital of Jonglei state, and even before the current unrest, it was seen as one of the most volatile areas of South Sudan.
Profile: Riek Machar
- Central figure in Sudanese and South Sudanese politics for three decades
- Member of South Sudan's second-largest ethnic group, the Nuer
- Was a Sudan People's Liberation Movement (SPLM) commander and led a breakaway faction for some years in the 1990s
- After 2005 peace deal appointed vice-president of interim government, retaining the post after independence in 2011 until his dismissal in July 2013
Overnight there were reports of gun battles in the town, as renegade officers fought with troops still loyal to the president.
President Salva Kiir has blamed the violence on a group of soldiers who support Mr Machar, saying they tried to take power by force on Sunday night.
South Sudan has struggled to achieve a stable government since becoming independent in 2011.
The oil-rich country remains ethnically and politically divided, with many armed groups active.