Russia said Monday the leader of the Islamist insurgency in the North Caucasus was killed in a special operation, and militants confirmed his death.
Russia's National Anti-Terrorism Committee said that Aliaskhab Kebekov was "neutralised" during a special operation in the North Caucasus region of Dagestan.
Kavkaz Center website, used by rebels to release statements, confirmed Kebekov's death, saying that "our dear brother became a martyr."
Kebekov, 43, a native of Dagestan, took over as leader of the Caucasus Emirate group in 2014 after the death of its veteran Chechen leader Doku Umarov.
Russia included Kebekov on its federal list of terrorists and extremists. He was declared wanted in 2012 for taking part in an illegal armed group.
The United States named Kebekov a "global terrorist", citing his claimed readiness to carry out orders from al-Qaida
The Caucasus Emirate is an Islamist group created in 2007 that has claimed responsibility for a string of deadly attacks in a simmering insurgency.
It aims to establish an Islamist state in the region and has called for global jihad.
Rebel activity has dropped recently, but fighters have travelled from the North Caucasus to take part in conflicts abroad, particularly in the ranks of the Islamist state group fighting in Syria and Iraq.
Russia said Kebekov was killed with four others, including two regional leaders of the insurgents, during the security operation in the town of Buinaksk, which began Sunday and ended Monday.
Forces from Russia's FSB security force and interior ministry surrounded the rebels in a building and opened answering fire after attempts to negotiate broke down, the committee said.
The building where the rebels were hiding was destroyed during the fighting and the bodies were pulled out from under the collapsed walls, the Russian authorities said.
Dagestan's regional interior ministry published photos of a fire burning fiercely inside a collapsed building.
Those in the building included several women, who refused to leave, while a child was handed out and survived, Russia's anti-terrorism committee said.
Russia said Kebekov was directly involved in organising suicide bombings in the southern city of Volgograd in 2013 that killed 34 people.
It said he also played a crucial role in the financial structure of the Caucasus Emirate "practically organising the extortion of money from the public."
Kebekov had been Umarov's deputy, acting as a judge imposing Islamic sharia law, according to Kavkaz-uzel.ru website, which focuses on the Caucasus.
Rebels announced Umarov's death, declaring him a martyr in March 2014. Russia's FSB security service later announced it had "neutralised" Umarov.
Umarov had previously been claimed dead numerous times by the Russian authorities, only for him to resurface in videos calling for jihad.
Under Umarov, the militants claimed responsibility for attacks including the 2004 Beslan school hostage crisis in which more than 330 died and the 2011 suicide bombing in Moscow's Domodedovo airport that killed 37 people.