Officials in the Democratic Republic of Congo have integrated more than 6,000 rebels into the army as part of an effort to end the conflict in the eastern DRC.
DRC Defense Minister Charles Mwando presided over the ceremony Thursday at a military barracks in the city of Rumango. North Kivu Province Governor Julien Paluku also took part.
The ceremony was to have been held Wednesday, but was postponed following delays and confusion.
At the ceremony, former rebel military commander Bosco Ntaganda was named second-in-command of the joint military brigades. An international mediation group headed by former Nigerian President Olusegun Obasanjo walked out of the ceremony in protest.
Ntaganda is wanted by the International Criminal Court on charges of using child soldiers during hostilities in Congo's Ituri province in 2002 and 2003.
The rebel Congress for the Defense of the People (CNDP) was fighting the Congolese government as recently as two months ago but ended its battle soon after the group's leader, General Laurent Nkunda, was arrested in Rwanda last week.
A short time before Nkunda's arrest, Ntaganda said that he had overthrown Nkunda and was ready for peace. He had said his group would work with Congo's army to fight ethnic Hutu militias active in eastern Congo.
Congolese and Rwandan soldiers recently launched a mission to subdue the militiamen, some of whom took part in the 1994 Rwandan genocide.