Traces of bomb found at Russia train wreck

Russian investigators discovered traces of an improvised bomb Saturday on the rail line between Moscow and St. Petersburg, where a train derailment killed at least 26 people in what appeared to be the nation’s worst terrorist attack in years outside the volatile North Caucasus.

The device exploded with the force of 15 pounds of TNT as a popular luxury express train, the Nevsky Express, passed over it Friday night in a wooded area about 200 miles northwest of Moscow. The blast threw at least three carriages from the tracks, injuring as many as 100 passengers and leaving a 5-foot-deep crater.

Russian authorities named no immediate suspects or motive, but the investigation was expected to focus on Muslim radicals who have stepped up attacks this year in a separatist insurgency in the volatile North Caucasus region, including Chechnya, Ingushetia and Dagestan.

If their involvement is confirmed, the attack on the Nevsky Express would mark a bold escalation by rebels who the Kremlin and its main ally in the region, the Chechen strongman Ramzan Kadyrov, insist are on the run and all but defeated – and a potential return to the violence that terrorized Moscow and other Russian cities in the first half of the decade.

Though shootings and bombings are a daily occurrence in the North Caucasus, more than five years have passed since the militants last staged a deadly strike outside the region. The rebel leader, Doku Umarov, issued a video in April, however, declaring civilians legitimate targets and vowing a fresh wave of violence across Russia.