The Omarska gained infamy as one of the worst concentration camps set up during the wars on the territory of the former Yugoslav federation in early 1990s.
The camp detained over 3,000 Bosnian Muslims and Croats.
The head of the "Prijedor 92" association of the camp's prisoners, Mirsad Duratovic, said that some 700 people died during the detention.
Mirsad Duratovic said that the statistics kept by the Prijedor police showed that 3,334 persons had been taken to the Omarska camp. Among them there were 38 women, 28 persons under age 18, and 68 prisoners older than 60 years.
Present at today's commemoration was Ed William, the Guardian's correspondent, who managed to enter the camp on 5 August 1992, a day before it was dissolved and took pictures and wrote a report about poor conditions in the camp, which shocked the world.
William called on local authorities and managers of the Mittal Steel company that now owns the Omarska mine to help construct a monument in tribute to the victims of the former concentration camp.