Caucasus insurgents trouble Russia for decades

MOSCOW Although there has been no claim of responsibility for the two bombings in Volgograd that killed at least 31 people in less than 24 hours, suspicion quickly fell on Caucasus rebels who have tormented Russia with terrorist attacks for nearly two decades. The insurgency has its roots in wars fought between separatist Chechen rebels and Russian forces, but it has spread throughout the North Caucasus region, which includes several mostly Muslim republics. Most assaults have been within the Caucasus, but attackers have occasionally reached far outside the region, including Moscow. Volgograd, which borders the North Caucasus...