Juba: At least 105 people have died in violence between government forces and rebel militias in Southern Sudan this week, an official said Sunday, raising concerns of southern instability ahead of the region's independence declaration in July.

Brigadier Malaak Ayuen, the head of the Southern Sudan's Army Information Department, said fighting on Saturday between a group of rebels led by Major General Gabriel Tanginye in Jonglei state and southern government forces led to 57 people being killed and scores being injured.

Ayuen said that five days of fighting between government forces and those loyal to another rebel chief, Peter Gatdet, in Unity state which is northwest of Jonglei, led to the deaths of 48 people. He did not give a breakdown of the number of civilians, rebels and the army killed in both incidents.

Since its January independence referendum, Southern Sudan has seen a wave of violence that has killed hundreds.

The south voted nearly unanimously to secede from the north, but there are many issues that still remain unaddressed including the sharing of oil revenues, the status of southerner and northerner minorities living on both sides of the border, and who controls the disputed border region of Abyei, a fertile area near large oil fields.

Southern officials now claim the militia groups they are fighting are being funded by the north to cause instability with the goal of taking over the oil fields in the south.

Before this week's violence the UN said that at least 800 people had been killed and 94,000 displaced because of violence in Southern Sudan this year.