A Bosnian Serb war crimes suspect, Sredoje Lukic, has surrendered to the Serbian authorities, government sources in Belgrade say.
Mr Lukic, in hiding for more than five years, was indicted by the UN tribunal in the Hague for crimes allegedly committed during the Bosnian war.
The 44-year-old is accused of being a member of a paramilitary group which killed and tortured Bosnian civilians.
His cousin, Milan Lukic, was arrested in Argentina in August.
Sredoje Lukic is expected to leave for the Hague on Wednesday, a government source told AFP news agency.
He has been indicted by the UN tribunal for alleged crimes committed in Bosnian-Serb controlled territory during 1992-95.
It is not clear where or when he was detained. Officials said it was the result of co-operation between Serbian and Bosnian Serb security services.
Milan Lukic, the alleged leader of the paramilitary group, is still in Argentina, awaiting extradition.