The Caucasus mountain range helps form dividing lines between Europe and Asia and between Russia in the North and Arabic lands to the South. While Russia is accustomed to tense relations in the region (with Chechnya, Dagestan and Georgia) security officials said tourists have rarely been targets.

Russia has beefed up security in recent days with police searching for the assailants. But those kinds of ongoing efforts will bring additional costs to what could be an expensive Winter Olympics that some estimate could cost $12 billion in infrastructure projects.

"Terrorism is a global phenomenon and no region is exempt," said a spokesman with the International Olympic Committee. "At the Olympics, security is the responsibility of the local authorities, and we have no doubt that the Russian authorities will be up to the task."

Terrorism cropped up at the Summer Games in Munich in 1972 and Atlanta in 1996, as the international event raises a region's profile. Before the 2002 Winter Olympics in Salt Lake City, officials added extra security measures because of the tragedy in New York on Sept. 11, 2001. "The last thing anyone wants is there to be a terrorist attack when all of the nations are gathered together for such a peaceful event," said Jessica Kunzer, a spokeswoman at Ski Utah in Salt Lake City.

But preventing terrorism around ski resorts is not particularly easy. "A facility has to recognize its resources, and with that, its limitations," said Chad Jones, a spokesman for Big Sky Resort in Montana, which has hosted President Barack Obama and Vice President Joe Biden in recent summers.

Big Sky's parent company, Boyne Resorts, hosted four Olympic events at its Cypress Mountain resort during the Vancouver Winter games in 2010. "Resort companies are in the hospitality business, so our scope goes to accommodating the needs of security, but not actually conducting high level security directly."