Russia Blames Terrorism for Downed Jet MOSCOW - Russian officials accused terrorists Friday after the wreckage of one of two crashed jetliners revealed traces of an explosive used in earlier attacks blamed on Chechen rebels, while an Islamic group claimed its suicide attackers brought down both planes.    At least one crash was "the result of a terrorist act," a spokesman for the Federal Security Service, Sergei Ignatchenko, told the ITAR-Tass news agency...