Terrorism is all too common in Russia, especially in its southern regions.
Just last week, a bomb killed two people at a shopping mall in Dagestan.
"It is a hotbed for Islamic extremism," says foreign policy expert Dr. William Martel of the Fletcher School at Tufts University.
It’s the kind of extremism that may have influenced alleged Boston Marathon bombers Tamerlan and Dzhokhar Tsarnaev.
Martel says the attack puts Russia back on the U.S. policy radar.
"It's been on again, off again. It'll become a lot more fixed in the public mind, the American mind, because now we have these extremists, these suspects, who spent time varyingly in Dagestan and Chechnya," he says.
The FBI is closely reviewing elder brother Tamerlan's visit to Dagestan last year where he reportedly met with militants. Russian authorities alerted the US as early as 2011 that he might be linked to radical Islamic groups. Martel says the U.S. should have paid more attention to those warnings and these regions, "but we've had a global agenda dealing with extremism. It's the Middle East, it's a lot of places around the world that we've had to deal with extremism, so I think there's we can work more with Moscow on this."
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