Juba: At least 30 people were killed when militia opposed to the Southern Sudanese government launched a failed overnight raid on a strategic town, said army and UN officials.

Fighting between Sudan People's Liberation Army forces and a militia led by a man known as Captain Olonyi started on Saturday outside the capital of the oil-rich border state of Upper Nile in the early hours of Saturday morning, said UN spokeswoman Hua Jiang. Olonyi is a little-known militia leader from a discontented minority ethnic group.

Jiang said the southern army repelled the attack on the city of Malakal.

At least 30 rebels were killed and four government soldiers were killed, said army spokesman Colonel Philip Aguer. He did not have figures for civilian casualties.

"Twenty-one people have been admitted so far to the hospital, including three young children," said Bartholomew Pakwan Abwol, a spokesman for the Upper Nile state government.

Abwol said many of those admitted had suffered bullet wounds.

"The [army] is in control of Malakal," he said. "They didn't attack the SPLA headquarters, they were attacking the centre of town."

Last Sunday, 62 people were killed and 71 wounded in fighting between Olonyi's forces and the southern army in a village north of Malakal, according to an internal UN security report released after the attack and viewed by The Associated Press.