Chechen rebel leader Doku Umarov has said his forces will carry out more attacks and that Russia faces a year of "blood and tears" if it refuses to abandon its North Caucasus territories.
In an Internet video posted on the Islamist website www.kavkazcenter.com, the bearded Umarov, dressed in a cap and military fatigues, said "a brother" was being sent to Moscow to carry out an unspecified special operation.
This appeared to be the young man standing at his left.
"We have to carry out our operation in order to wake you up. If this is not enough, then God willing, other blows will follow," Umarov said.
The video made no reference to the Moscow airport bombing that killed 36 people in late January.
A decade after federal forces drove separatists out of power in Chechnya in the second of two wars, the North Caucasus is plagued by violence the Kremlin has failed to contain.
"I can tell you with 100 percent confidence...if God is with us then this year will be a year of blood and tears," Umarov said.
The video, which shows Umarov flanked by the young man and a rebel commander standing beneath a black flag with a white sword below Arabic script, does not include any information about when it was filmed.
As the self-styled Emir of the Caucasus, 46-year-old Umarov has sought to create a pan-Caucasus state independent from Russia and governed by sharia law, which would include Chechnya, Dagestan and other nearby mainly-Muslim provinces in Russia's south.
Umarov's speeches are posted occasionally on the Kavkaz Centre site, and his insurgency has claimed responsibility for a number of deadly bombings in the past.
Russian officials last week said the Domodedovo suicide bomber was a 20-year-old native of the North Caucasus, though they did not release his name, citing the ongoing investigation.
No group has claimed responsibility for the attack, but North Caucasus officials have directly pointed the finger of blame at Umarov.
In the video, Umarov said he is visiting the battalion of martyrs Riyadus-Salikhiyn, and that 50-60 potential "martyrs" were prepared to further his cause.
"God willing, depending on your reaction and your actions, these operations will continue every month, every week, as God allows us," he said.
The Riyadus-Salikhiyn battalion took responsibility for the 2004 Beslan school massaccre where more than 320 people died, as well as more recent actions such as a deadly September market bombing in Vladikavkaz in the North Caucasus.
