CONAKRY, Guinea — Guinea’s military junta appointed a veteran opposition leader Tuesday as the country’s new prime minister, a crucial step that sets the stage for the military to cede power to civilians in elections within the next six months.

Jean-Marie Dore is an outspoken critic of junta leader Capt. Moussa “Dadis” Camara and was brutally beaten by his soldiers when he helped lead a demonstration calling for an end to military rule.

The appointment came as Gen. Sekouba Konate, who has been acting as the country’s interim leader after persuading Camara to step aside and accept a transition to civilian rule, returned to Conakry amid extremely tight security.