The Council on Foreign Relations points out that Russian President Vladimir Putin has often stressed that international terrorists operate in Chechnya, adding that Putin seeks to generate Western sympathy for Russia's military campaign there.
An International Crisis Group report published in October 2012 warned that continued ethnic, religious, political and economic grievances could bring increased tensions in the North Caucasus region, adding: "The killing is unlikely to end soon."
Chechen leader Ramzan Kadyrov on Friday distanced his republic from the brothers in Boston. "Any attempts to link Chechnya and the Tsarnaevs if they are guilty are vain," he said via his official Twitter account.
"They grew up in the U.S. and their views and beliefs were formulated there. So you need to look for the roots of the evil in America.
"The world should fight terrorism together. We know it better than anyone. We wish all those suffering to recover soon and we share the grief of Americans."
Meanwhile, Kyrgyzstan's state committee for national security said that the two brothers had moved with their family to Dagestan 12 years ago, and from there to the United States.
Given that the boys were aged 8 and 15 when they left the country, the committee said, it "considers it inappropriate to link them to Kyrgyzstan."
An official in the Central Asian republic of Kyrgyzstan earlier told CNN the brothers were Kyrgyz passport holders and used those passports when applying for residency Green Cards in the United States.