Chechnya's guerrilla chief and self-proclaimed "Emir of the Caucasus" Doku Umarov, 46, has evaded capture in the thickly forested valleys of the Caucasus mountains for almost two decades, although Russian authorities have several times prematurely announced his death.
The bearded rebel fighter had been on Russia's most-wanted list long before the bloody metro bombings that killed 39 people, for battling pro-Kremlin forces in two separatist wars in Chechnya since 1994.
But in October 2007, Umarov styled himself as head of the "Caucasus Emirate", uniting rag-tag rebel groups in several southern Russian regions in a drive to establish Sharia, or Islamic rule, in the North Caucasus.
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In his claim for the Moscow strikes posted March 31 on a radical North Caucasus website, Umarov vowed more attacks on the Russian heartland: "The war will come to your streets, and you will feel it with your own lives and skins."
He was known as an ally of notorious rebel chief Shamil Basayev, who claimed to have led dozens of bloody attacks, including the infamous 2004 Beslan school hostage siege that killed over 330 people, most of them children.Umarov became head of the Chechen guerrilla movement in June
2006 after Basayev was killed by Russian forces a month earlier.
The two rebels were at the forefront of the Chechen separatist struggle in which as many as 100,000 civilians, or about 10 per cent of the region's mostly Muslim population, are feared to have been killed.
