Serbian police are searching three locations for the war-crimes fugitive Ratko Mladic, official sources say.
They are searching two locations in the capital Belgrade as well as a tourism centre in Arandjelova, a village in central Serbia.
Gen Mladic is accused by international prosecutors of genocide while leading Bosnian Serb forces in 1992-95.
Serbia is under pressure to bring Gen Mladic to justice as part of its efforts to enter the European Union.
The government recently raised its reward to 10m euros (£8.7m, $13.8m) for information leading to his capture, saying that demonstrated its commitment to removing "the last remaining obstacle on its path towards the EU".
The chief UN war crimes prosecutor for the former Yugoslavia, Serge Brammertz, is set to visit Serbia shortly to evaluate if Serbia is doing its best to apprehend Gen Mladic.
Police are searching "a private residence and a restaurant in Belgrade and a so-called ethno village close to Arandjelova," a source close to the war crimes prosecutor told the news agency AFP on condition of anonymity.
All three sites are thought to be owned by people close to Gen Mladic.
Aged 68, Gen Mladic has been on the run since the end of Bosnia's civil war.
He was jointly indicted with Radovan Karadzic on charges of genocide, war crimes and crimes against humanity by the International Criminal Tribunal for the former Yugoslavia (ICTY) in The Hague in 1995.
Mr Karadzic was captured in 2008 in Belgrade, where he was living in disguise and under a false name, and is currently on trial at The Hague.