(CNN) -- Chechen warlord Doku Umarov, one of Russia's most wanted men, has died, a Chechen jihadist website said Tuesday.
The Kavkaz Center website said Umarov would be replaced as leader of the Islamist group Caucasus Emirate by Ali Abu Mohammed.
Umarov has frequently been reported as killed or wounded in combat. The report of his death has not been independently confirmed.
The website did not say when or how Umarov had died. It called him "a martyr."
The U.S. State Department said Umarov organized a suicide bombing outside the Chechen Interior Ministry in May 2009. His group also claimed responsibility for the bombing of Domodedovo Airport in Moscow in 2011 that killed 36 people, the 2010 bombings of the Moscow subway that killed 40 people, and the 2009 bombing of the high-speed Nevsky Express train in which 28 people died.
Umarov was a seasoned fighter who survived more than six years as the self-styled leader of the Caucasus Emirate.
The Caucasus Emirate, or Imarat Kavkaz, has its roots in the 1990s Chechen insurgency.
Umarov had called on his followers to do what they could to disrupt last month's Winter Olympics in Sochi, Russia.
He claimed the Games were being held on the graves of Muslim occupants of Sochi, who he said were driven out by Russian imperial forces in the 19th century.
CNN's Tim Lister and Laura Smith-Spark contributed to this report.