Militants from Chechnya and neighboring provinces have carried out a long series of terrorist attacks in Russia, including a 2002 raid of a Moscow theater, in which 129 hostages died; a 2004 hostage-taking at a school in the southern city of Beslan that killed more than 330 people, and numerous bombings in Moscow and other cities.
The Obama administration placed Chechen warlord Doku Umarov on a list of terrorist leaders after he claimed responsibility for March 2010 suicide bombings on Moscow's subway that killed 40 people and a November 2009 train bombing that claimed 26 lives.
In recent years, however, militants in Chechnya, Dagestan and neighboring provinces have largely refrained from attacks outside the Caucasus.
Russian officials and experts have claimed that rebels in Chechnya had close links with al-Qaida. They say dozens of fighters from Arab countries trickled into Chechnya during the fighting there, while some Chechen militants have gone to fight in Afghanistan.
The U.S. has long urged Russia's government and separatist elements in Chechnya not aligned with al-Qaida or other terrorist organizations to seek a political settlement.