(CNN) -- More than 65 people have been killed in two days of clashes between rebel groups and soldiers in Southern Sudan's Upper Nile state, an army spokesman said. 

Philip Aguer, spokesman for the Sudan People's Liberation Army (SPLA) told CNN.com that forces loyal to a militia leader named Oliny attacked the village of Uach west of Malakal in Upper Nile state. 

"55 members of the militia and seven SPLA soldiers were killed, and we believe a number of civilians also died, but we are still getting information." 

Oliny, Aguer said, is a former member of Southern Sudanese politician Lam Akol's militia. "But we don't know if he is still associated with him." 

Aguer also said that he believes that Oliny was receiving military support from the government in northern Sudan. 

"They have received new weapons. We suspect they all acted in coordination with Khartoum ... I think things are going to continue escalating," he said. 

However, Sudan's dominant National Congress Party (NCP) in the north denied having any involvement. 

Rabie Abdelati, an NCP party official, said on Monday: "If we really wanted to go back to war, we would not have signed the Comprehensive Peace Agreement (the 2005 accord) or accepted the referendum. 

"We are hoping for a strong south after secession. If the south is not stable the north will not be stable," he said. 

Akol, a seasoned Southern Sudanese politician and a former member of the SPLA, broke from the SPLA in 2009 and created a new party, the Sudanese Peoples Liberation Movement-Democratic Change (SPLM-DC). 
how many people have been killed ?
More than 65 people