An overwhelming number of south sudanese voted for independence from the north [Reuters]

A rebellion by former pro-Khartoum fighters in the Upper Nile state of south Sudan against giving up their heavy weapons has sparked two days of clashes, leaving 20 people dead and at least 24 injured.

The fighting around Malakal airport, close to the border with the north, began on Thursday when loyalists of Gabriel Tang, who commanded a pro-Khartoum force during the 1983 to 2005 civil war, objected to surrendering their heavy weaponry.

The dead included two children and a Sudanese driver for the UN's refugee agency, officials said.

The Tang loyalists are deployed alongside regular Sudanese Armed Forces (SAF - the northern army) in so-called Joint Integrated Units (JIUs) with former Sudan People's Liberation Army (SPLA) forces that patrol the town under the peace agreement that ended the civil war.

In reality the units are far from integrated and the component elements effectively operate as separate forces.

The northern troops are shifting their equipment back home as the south gears up for its expected international recognition as an independent state in July following its overwhelming vote for secession in last month's landmark referendum.

"The number of dead has risen to 20, and this could change at any moment," southern army spokesman Philip Aguer said on Saturday.

"Searches are continuing and many are wounded ... Both sides were firing mortars and heavy machineguns."

The military warned there was a risk of more clashes as the country divided its forces before the south became independent.

Peter Lam Both, Upper Nile's information minister, said fighting had also erupted in three other areas of the state on Saturday morning - Paloich, Malut and Maban.

Splitting operations

"Our forces in the SPLA, along with the United Nations peacekeepers, have succeeded in creating a buffer zone between the two sides and to bring the situation to an end," Aguer said.

The incident underlined the challenges facing Sudan as it tries to untangle joint operations before the split.

Bartholomew Pakwan Abwol, spokesman for the government of the surrounding Upper Nile state, said the protesting SAF soldiers were ethnically southerners.

"Some are refusing to go north and be disarmed. They are southerners and they have rights here. But they think they will have no rights in the north," he said.

Northern and southern leaders still have to finalise how they will share out military hardware and security forces - as well as oil revenues and debts - before the south's departure, expected on July 9.

Many fear tensions could re-emerge during the negotiations.

The week-long referendum, held in January, had been promised in a 2005 peace deal that ended a decades-long civil war between north and south, and caused internal conflicts that have left deep scars.

Source: Agencies