Russian officials are still investigating a pair of suicide bombings that killed at least 31 people in the city of Volgograd, but there has yet to be any claim of responsibility or known motive behind the blasts.
But, speculation immediately turned to the volatile North Caucasus region and Chechen rebel leader Doku Umarov.
He has claimed in the past he gave the orders for several other deadly attacks on Russian soil, including the Moscow airport bombing nearly two years ago, double suicide bombings on the Moscow subway in 2010, and a 2009 passenger train attack.
He was also said to be linked to the 2004 siege of a school in Beslan — a terrorist attack that ended with the deaths of more than 380 people.
But the 49-year-old militant gave a warning earlier this year that the Sochi Olympics may be in his sights.
“We know that on the bones of our ancestors, on the bones of many, many Muslims who died and are buried on our territory along the Black Sea, today they plan to stage the Olympic Games. We, as the Mujahedeen, must not allow this to happen by any means possible,” Umarov said in a video message posted online in July.
The suicide bombings on Sunday and Monday took place in the city of Volgograd, about 990* kilometres northeast of the Black Sea resort city where the Olympics will get underway on Feb. 7.
The attacks could be seen as a way of trying to rattle Russia’s nerves ahead of the Games.
Volgograd is a key transport hub that many travellers will pass through en route to Sochi.
WATCH: Do bombings threaten Russia’s ability to safeguard the Olympic Games?
It’s not the first time Umarov has been accused of plotting to attack the Olympic Games site.
Russia’s Federal Security Service and National Anti-Terrorist Committee claimed to have foiled a terrorist plot in 2012, saying authorities seized weapons and ammunition — including portable surface-to-air missiles, landmines and grenade launchers — in the Georgian breakaway republic of Abkhazia, less than 200 kilometres away from Sochi.
Umarov has led an Islamist insurgent organization known as the Caucasus Emirate — a group he formed in 2007, one that declares itself a part of a global jihad and aims to form an Islamic state, or Emirate, in the Northern Caucasus region.
The Emirate would include territories such as Chechnya, Dagestan, Ingushetia and North Ossetia, as well as Krasnodar Krai — the federal subject of Russia where Sochi is situated.
Prior to forming the Caucasus Emirate, Umarov was the president of the Chechen Republic of Ichkeria — a “self-proclaimed secessionist government of Chechnya.”
“The Caucasus Emirate has carried out terrorist activities in Russia, resulting in the death and injury of many Russian civilians and security personnel. Listing these organizations as terrorist entities sends a strong message that such actions will not be tolerated,” Minister Stephen Blaney said.
“Listing terrorist entities facilitates the prosecution of perpetrators and supporters of terrorism, as well as countering terrorist financing,” Blaney said.
The U.S. government and the United Nations gave the same designation to Umarov’s group in 2011.
With files from The Associated Press
*CORRECTION: An earlier version of this story stated Sochi is 650 kilometres from Volgograd. The distance between the two stories is approximately 990 kilometres
© Shaw Media, 2013