The leader of the Ugandan rebel group the Lord's Resistance Army says he will not attend peace negotiations with the Ugandan government to end nearly two decades of fighting. The next round of negotiations is due to begin Friday in the southern Sudanese town of Juba.

The latest peace talks are to be mediated by southern Sudan's Vice President Reik Machar. He traveled Wednesday to the Congolese border to urge Lord's Resistance Army leader Joseph Kony to join in the peace process.

An aide to Vice President Machar says Kony refused to meet with him and instead sent his second in command, Vincent Otti. He reportedly told Machar that the rebel group would not be sending any of their top five commanders to the talks because they fear they will be arrested.

A year ago, the International Criminal Court based in The Hague indicted the five men on charges of crimes against humanity. The rebel group has been accused of causing the deaths of tens of thousands of people, displacing more than one million others, and kidnapping as many as 30,000 children to fight as soldiers and serve as sex slaves.

The Ugandan government has already pledged to give the rebels full amnesty if they commit to the peace process.

Political editor Charles Mwanguhya of the Ugandan newspaper, the Daily Monitor, says that without the senior leadership of the Lord's Resistance Army at the talks, this latest attempt to establish peace in northern Uganda will likely fail.

"The ICC has provided a very good opportunity for Kony to stay away. It is an excuse for Kony and his people," said Mwanguhya. "We are seeing the talks becoming weaker and weaker and the outcome more uncertain. Uganda has sent very senior people to do the talks and if they cannot talk to people at the same level, we cannot expect any of the two parties will make headway with these talks."

Ugandan government spokesman for the talks, Robert Kabushenga, says that his government has no plans to downgrade its negotiating team to a more junior level. He says the government remains optimistic that there will be another opportunity to meet with Kony and his senior commanders in the near future.

"They are the decision makers of LRA. However, if Dr. Reich Machar says these people have been mandated to carry on with the talks, our people will turn up," noted Kabushenga. "The feeling here is that whatever happens, whatever the outcome, people here are more or less in the mood to go. So, they will turn up in at some point when they realize we are serious."

The government has imposed a September 12 deadline for the rebel group to negotiate a peace settlement. It is unclear what will happen if the rebels miss that deadline.

Meanwhile, the Ugandan army says Wednesday it captured the most senior rebel commander still operating in northern Uganda. A spokesman for army, Major Felix Kulayigye, says the capture of the rebel commander should not affect the peace process.

"Their decisions have nothing to do with what transpired yesterday. As I have said, there was no ceasefire," said Kulayigye.  "None of the sides declared cessation of hostilities. Operations continue as normal."

Several peace deals between the Lord's Resistance Army and the Ugandan government have failed, with both sides accusing the other of violations.