Chechen separatist leader Abdul-Khalim Sadulayev has been killed by pro-Russian forces during a special police operation.
The head of Russia's Federal Security Service, Nikolai Patrushev, says an FSB agent and a police officer were killed during Saturday's operation, which took place in Argun, near the Chechen capital, Grozny.
Separatist officials say senior militant Doku Umarov is likely to succeed Sadulayev as president of Chechnya's breakaway government.
Chechen Prime Minister Ramzan Kadyrov said one of Sadulayev's aides sold information about his whereabouts to police. The prime minister also said the rebels were plotting a terror attack in Argun ahead of the Group of Eight summit set for St. Petersburg in July.
Sadulayev became the separatist leader after chief Aslan Maskhadov was killed in March 2005 in a raid by Russian forces.
The Russian republic of Chechnya has been plagued by a decade of bloody fighting between separatists and Russian government forces.
Some information for this report was provided by AFP, AP and Reuters.