They accused the former and current governments in Belgrade for failing to show enough understanding for their problems.
They also criticised Croatia for a lack of cooperation in taking samples of blood for DNA methods of identification.
The head of the association of families whose members went missing in the so-called Krajina (Croatian areas held by Serb rebels in the early 1990s), Cedo Maric told the conference that according data possessed by this association, 3,000 persons had still been unaccounted for.
Maric added that his association's representatives and the Hague-based UN war crimes tribunal's investigators had a month ago visited northern Dalmatia where they registered 10 locations as possible mass graves in which those killed during the 1995 Operation Storm were buried.
The news conference in Belgrade was held on International Missing Persons Day.