The junior party in Serbia's governing coalition has suggested forcing early elections if top war crimes suspect Ratko Mladic is not captured soon.
The Mladic family home was among the properties searched
Politicians from the liberal G17 Plus party have said the government must transfer the Bosnian Serb general to the tribunal in The Hague by September.
The leader of G17 Plus, Miroljub Labus, has already resigned as Serbia's deputy prime minister.
Serbian police have stepped up their hunt for Gen Mladic in recent days.
He is wanted by the international tribunal in The Hague on charges of genocide relating to the massacre of about 8,000 Muslim men and boys from Srebrenica in 1995, during the Bosnian war.
Last week Mr Labus resigned from the government after the failure to apprehend Gen Mladic led the European Union to freeze talks on closer ties with Serbia.
President Boris Tadic said on Saturday he hoped Gen Mladic would be arrested by 10 May - the day before cancelled EU talks were due to be held.
At least 12 people have been detained in recent weeks in the hunt for Gen Mladic.
On Saturday, Serbia and Montenegro's Foreign Minister Vuk Draskovic called for senior security officials to be dismissed over their failure to detain Gen Mladic.