Last month, he vowed to take the Islamist battle to Russia's cities, and he says the attacks will continue:

Chechen rebel leader Doku Umarov has claimed responsibility for Monday's suicide bombings in the Moscow subway system.

Umarov, who leads Islamist militants in Chechnya and nearby regions of Russia's North Caucasus, says he personally ordered the attacks.

In a video posted on the Islamist rebels' unofficial Web site Wednesday, Umarov says the twin bombings were retaliation for Russian security forces killing civilians in the Caucasus.