Several world leaders have offered their support and condolences over the deadly bombings in Volgograd while the Russian Foreign Ministry called for joint efforts to fight terror attacks that follow "the same template" around the world.
In a statement on Monday, the Foreign Ministry said that Russia "will not retreat and will continue a harsh and consistent fight against the insidious enemy that knows no borders and that can only be stopped by joint efforts."
The two bombings at a train station and a trolleybus in Volgograd that left more than 30 people dead "are organized according to the same template" as other terror attacks around the world, the ministry said.
The White House condemned the attacks and offered "full support to the Russian government in security preparations for the Sochi Olympic Games," National Security Council spokeswoman Caitlin Hayden said. The Games are to begin in less than six weeks at the Black Sea resort 700 kilometers from Volgograd.
British Prime Minister David Cameron said he was "shocked and saddened" by the attacks.
"I've written to President Putin to say the UK will help Russia in whatever way we can," Cameron said in a Twitter message.
The Volgograd attacks bear out a threat that Chechnya's terrorist leader Doku Umarov made in July, when he called on his supporters to apply a "maximum effort" to disrupt the Sochi Games "by any methods that the almighty Allah allows us."
Umarov, who also claimed responsibility for the 2011 bombing at Moscow's Domodedovo Airport, lifted the moratorium on civilian targets in Russia that he had declared amid the 2011 anti-government protests in Moscow.
In an online appeal for terror, he urged his followers to undermine "those satanic dances on the bones of our ancestors", referring to Muslims who lived along the Black Sea coast.
The U.S. State Department — which considers Umarov's Caucasus Emirate a terrorist group and has a $5 million reward for information on him — acknowledged the scope of his threats. Spokeswoman Marie Harf on Monday urged Americans who plan to attend the Sochi Games to "remain alert regarding their personal security at all times."
U.S. and Russian officials have been cooperating on preparations for the Games for months. Counterterrorism cooperation between the U.S. and Russia has increased after last April's Boston Marathon bombing, which was supposedly carried out by two ethnic Chechens.
Pentagon spokesman Steven Warren said joint exercises, such as the Operation Vigilant Eagle counterterrorism exercise which began in 2009, has also improved relations between the two countries' security forces. Bilateral military cooperation "is as good as it's ever been," Warren said on Monday.
The UN Security Council said it was "outraged" by the "abhorrent and abominable attacks."
The 15-member council "urged all states, in accordance with their obligations under international law and relevant Security Council resolutions, to cooperate actively with all relevant authorities in this regard," it said in a statement.
The UN Secretary-General Ban Ki-moon spoke to Russian President Vladimir Putin on Monday to express his condolences to the families of the victims and "stressed the importance of strong international cooperation to fight terrorism," Ban's office said in a statement.
International Olympic Committee President Thomas Bach condemned the bombings as "a despicable attack" and said he had written to Putin to express "our confidence in the Russian authorities to deliver safe and secure Games in Sochi."