Moscow (CNN) -- The leader of Islamist rebels suspected of bombing Moscow's main international airport last month is pledging to step up deadly attacks in Russia.
In a video message posted Sunday on a pro-rebel website, Doku Umarov stopped short of claiming responsibility for the January 24 airport bombing, which left 36 people dead.
But the self-titled Emir of the North Caucasus vowed to deliver "a year of blood and tears" to Russia, saying that there were dozens of rebels prepared to carry out attacks.
"I won't tell you there are hundreds of us prepared for Jihad. But 50 or 60, God willing, we will find," Umarov said in Russian, wearing camouflage combat fatigues.
"Those operations will be conducted monthly or weekly, as Allah allows us," he said.
In Moscow, investigators say they have identified the suspected suicide bomber as a 20-year-old man from the North Caucusus region.
Alexander Bortnikov, the head of Russia's Federal Security Service, has refused to publicly name the suspect or identify his specific origin.
But he told Russian state television the alleged bomber was under the influence of drugs before the attack.
"Biological studies revealed the presence of a huge amount of highly potent narcotic and psychotropic substances in parts of the suicide bomber's body," Bortnikov said.
Sunday's video message from Umarov was posted on a website that often carries messages from the rebel leadership.
Sitting beneath a black flag and flanked by two other bearded rebels, Umarov names the young man to his left as "Mujahedeen Seifullah."
He said the man was being sent on a mission, although it is not clear from the video if this was the suspected Moscow airport bomber, or when the message was recorded.
"I would like Putin and Medvedev and all other kaffirs and enemies to understand that there are many of us who will follow in our footsteps and give their lives for Allah," Umarov said.
