Chechen leader Ramzan Kadyrov has said that he has new evidence that rebel leader Doku Umarov is dead, just weeks before the Winter Olympics start amid fears over security in the host city of Sochi.
"According to our information, Umarov is dead and we are looking for his body," Kadyrov said late Thursday, NTV television channel reported.
Kadyrov said that Umarov was killed during a special forces operation, without providing further details.
Writing later on social media site Instagram, Kadyrov said that intercepts of a recent conversation between senior North Caucasus militants included a discussion of Umarov's death and disagreements over his replacement.
Unidentified security services officials said Thursday that there was no confirmation that Umarov was dead.
Russia has been plagued by security concerns in the run-up to the Winter Olympics, with a double suicide bombing in the southern Russian city of Volgograd last month highlighting the risks.
Sochi is several hundred kilometers from the North Caucasus, which has been wracked by an Islamist-inspired insurgency for more than a decade.
In an address to his followers in July 2013, Umarov, leader of the radical Islamist Caucasus Emirate organization, called for the Olympics to be attacked.
The majority of the high-profile militant leaders in the volatile North Caucasus have been killed in recent years, but Umarov has consistently resurfaced after erroneous reports of his demise.
Umarov claimed responsibility for a number of Russia's worst terrorist attacks in recent years, including the 2011 bombing of Moscow's Domodedovo airport and 2010 attacks on the capital's metro system.