The NATO headquarters in Sarajevo said in a statement today that Tolimir was transferred to The Hague aboard a special plane.
An official of the Bosnian Serb entity's ministry of the interior, Gojko Vasic, told a news conference in Banja Luka that Tolimir was arrested while trying to cross the border between Serbia and Bosnia-Herzegovina without any documents.
The arrest was made by Bosnian Serb police, while Serbian authorities provided only intelligence data in this operation, Vasic said.
He reiterated that Tolimir had resided in Serbia before his arrest.
Tolimir was one of the seven assistants to the war-time commander of the Bosnian Serb army and ICTY indictee, Ratko Mladic.
He is charged with genocide, crimes against humanity, and violations of the laws and customs of war.
The German EU presidency welcomed Tolimir's apprehension and voiced satisfaction with cooperation between Bosnian and Serbian authorities in the operation.