Russian officials have presented to journalists a man they identified as Akhmad Umarov, the older brother of Chechen separatist leader Doku Umarov.
The man told reporters in Chechnya's second-largest city Gudermes that he surrendered voluntarily earlier Friday. He said he wanted to live and work legally.
His appearance followed a series of contradictory reports, one that the separatist leader himself had surrendered, and later that it was his younger brother.
Doku Umarov assumed leadership of the Chechen separatist movement in June after Russian forces killed his predecessor, Abdul-Khalim Saidulayev.
Chechen separatists have also been stung by last month's death of top Chechen warlord Shamil Basayev, who claimed responsibility for a number of spectacular attacks.
Last month, Doku Umarov dismissed a Russian offer of amnesty for all Chechen separatists. Russian troops have been fighting Islamic separatists in Chechnya for the past decade.
Some information for this report was provided by AFP, AP and Reuters.