MOSCOW – A website sympathetic to militants fighting Russian rule in the North Caucasus said yesterday the insurgency's leader, Doku Umarov, had been killed. The death of Russia's most wanted man, who called for attacks on last month's Winter Olympics in Sochi, has been reported before by the Kremlin-backed leader of the Chechnya region but not by Umarov's sympathizers.A spokesman for Russia's National Anti-Terrorism Committee was quoted by state news agency RIA as saying he could not confirm Umarov was dead. The Kavkaz Centre website did not say when or how Umarov had been killed. It called him a martyr who had "given 20 years of his life to the Jihad."