Joseph Kony, leader of the notoriously vicious Lord's Resistance Army, has not been seen publicly since 2006, when he went into hiding along the Sudan-Congo border.

"After today, there will be one less problem for the world," said Jean-Baptise Odama, archbishop of the northern Ugandan town of Gulu, who traveled to the spot near Kony's hide-out to witness the signing.

Kony's rebel force is known for cutting off the lips of its victims and for recruiting child soldiers. More than a year of peace talks, mediated by the Vice President of southern Sudan, Riek Machar, have been marked by walk-outs and accusations of sabotage on both sides.

Kony and four other members of the rebel high command are wanted by the International Criminal Court, so they have remained in hiding out of fear of arrest. President Yoweri Museveni says he won't turn them over if they end their insurgency.

U.N. officials estimate that the LRA has kidnapped 20,000 children in the past two decades, turning the boys into soldiers and the girls into sex slaves for rebel commanders.

If both sides reach a comprehensive deal, it will be a major breakthrough in pacifying the volatile region comprising northern Uganda, eastern Congo and southern Sudan. Rebels from all three nations operated across the borders with impunity for decades until a peace accord halted Congo's civil war in 2003 and southern Sudanese rebels joined Sudan's government in 2005.