South Sudan rebels attack key town
Analysts say there is little hope of a looming ceasefire deadline being heeded
Anti-government rebels in South Sudan have attacked the key town of Bor, just hours before a deadline for a ceasefire expires.
A UN spokesman said the fighting began at daybreak, not far from the town's UN compound.
A South Sudanese army spokesman confirmed a "big fight" had happened.
Uganda's president has threatened the rebels with military action if they fail to agree to a ceasefire by the end of Tuesday, and begin talks.
But the rebel leader, Riek Machar, has demanded the release of all his detained political allies before any talks can begin, something South Sudanese President Salva Kiir has rejected.
Ethnic conflict?
Only last week the army was celebrating the recapture of Bor from the rebel forces - but it now appears that the rebels are back, and have captured a key crossroads.
The UN believes the attackers are a mix of mutinous soldiers loyal to Mr Machar and an ethnic militia called the "White Army", known for putting white ash onto their bodies as a kind of war-paint.
In recent days, thousands of people have fled from Bor, the capital of Jonglei state.
South Sudan's president says he believes a peaceful solution is still possible
The fighting initially broke out more than two weeks ago in the capital, Juba, and has now spread to many parts of the country.
At least 1,000 people have died and more than 121,600 are believed to have fled their homes.
Mr Machar, who was President Kiir's deputy until he was sacked in July - is accused of mounting a coup that sparked the violence. He denies the allegation.
What began as a power struggle between the two men has taken on overtones of an ethnic conflict. The Dinka, to which Mr Kiir belongs, are pitted against the Nuer, from which Mr Machar hails.
Mr Kiir has ruled out any power sharing with Mr Machar, telling the BBC on Monday: "These men have rebelled. If you want power, you don't rebel so that you are rewarded with the power. You go through the process."
