MAKHACHKALA, Russia – Two powerful explosions derailed a cargo train Sunday in the violence-plagued Russian province of Dagestan but no one was injured, officials said. The blasts capped a week of daily attacks that have killed at least 55 people. A blast equivalent to five kilograms of TNT exploded early Sunday near the town of Izberbash, derailing the locomotive and eight cars, transport police spokesman Akhmed Magomayev said. Another, less powerful blast aimed at killing rescuers detonated nearby shortly after the first explosion, he said. The explosions "continued the pattern" of terrorist attacks against symbols of authority that included the November bombing of a high-speed train that killed 26 people near St. Petersburg, Magomayev said. Two suicide bombers killed 40 rush-hour commuters on the Moscow metro last week, shocking Muscovites as terrorism returned to the capital for the first time since 2004. On Sunday, the Emergency Ministry raised the number injured in the subway bombings to 121. The bombers, aged 17 and 20, were identified as widows of Islamic militants killed by Russian security forces last year. A Chechen militant leader claimed responsibility for the subway attacks as revenge for the Feb. 11 slaying of local garlic-pickers in a forest by Russian security forces. Dagestan is the epicenter of almost daily violence that has plagued Russia's predominantly Muslim North Caucasus region for years following two separatist wars in neighboring Chechnya. Prime Minister Vladimir Putin has vowed to "drag out of the sewer" the organizers of the subway bombings, and Prime Minister Dmitry Medvedev promised "crueler" measures to crack down on terrorism. In Kostek, a poor rural village in Dagestan, the family of 17-year-old Dzhanet Abdurakhmanova, one of the accused Moscow subway bombers, said Saturday they disowned her as soon as she was abducted into marriage by a militant.