Earlier this year, the Russian Interior Ministry claimed that over 400 volunteers from Russia's North Caucasus
republic of Chechnya joined ISIL.
In 2013, Caucasus regional police sources reported that Kebekov ordered the killing of Sheikh Said-Afandi Chirkeyskiy, a prominent moderate religious leader in the Republic of Dagestan, also in the North Caucasus
region of Russia, who was ideologically opposed to the Caucasus Emirate," the statement revealed.
Ali Abu Mukhammad, leader of the Caucasus Emirate, expressed his dismay with this development, saying that although the decision on where to wage jihad -- in the Middle East or Russia -- is up to individual fighters, "brothers" ought to return to the North Caucasus
"to start a war in Russia's southern regions.
In a videotaped address to Russian President Vladimir Putin posted on the Internet in September, the ISIL members threatened to wage war on the North Caucasus
A website sympathetic to the insurgency in the North Caucasus
said on March 18 that Umarov was dead but the Russian authorities had not previously confirmed the report.
Sochi is located in the North Caucasus
region, which, following the Soviet Union's dissolution, experienced a long and brutal armed insurgency in Chechnya, while neighboring Dagestan, in particular, later became a hotbed of Islamist extremism and terrorism.
The blasts are Russia's deadliest since a suicide raid on Moscow's Domodedovo airport that was claimed by Islamic insurgents from the North Caucasus
killed 37 people in January 2011.
The southern city of Volgograd planned to bury the first victims of Sunday's bombing of the heartland hub's main railway station that killed 18 people and which officials have provisionally blamed on a young woman from the restive North Caucasus
region of Dagestan.
The Olympic venue is close to Russia's volatile north Caucasus
According to the BBC, the Olympic venue is close to Russia's volatile north Caucasus
State prosecutors said the four had helped the suicide bomber travel from their native region of Ingushetia in the North Caucasus
to Moscow and providing him with an apartment, an explosives belt and transportation.
Hundreds of suspected rioters were held in the district of Biryulovo after the stabbing to death of an ethnic Russian man who allegedly was killed by a native of North Caucasus
, a region in southern Russia.