By Matt Prodger BBC News, Belgrade
An official investigation in Serbia and Montenegro has concluded that retired members of the military have helped hide former leader Ratko Mladic.
But a statement issued by the state Supreme Defence Council said his whereabouts were still unknown.
General Mladic is one of Europe's most wanted war crimes fugitives and has been charged with genocide.
This is the first time that the country's defence chiefs have admitted the military has helped Gen Mladic.
A statement issued by the Supreme Defence Council said that until 2002 Gen Mladic had, on occasion, been sheltered at army compounds in Serbia and that since then he had been supported by retired military officers.
The statement did not divulge their names but called for their arrest.
This is unlikely to impress international prosecutors, who insist that to this day Ratko Mladic continues to enjoy the protection of the Serbian military.
The same prosecutors also refuse to believe claims by the Serbian authorities that his current whereabouts are unknown.
Ratko Mladic was the head of the Bosnian Serb armed forces during the war and is wanted for his involvement in the siege of Sarajevo and the massacre of nearly 8,000 men and boys at Srebrenica in 1995.