A bomb went off early on Tuesday at the entrance to the traffic police headquarters in the southern Russian city of Volgograd, a local police spokesman said. No one was killed by the blast and no injuries were reported, Russia\'s News Agency (RIA Novosti) reported. The blast occurred in one of the city\'s central districts. The explosion was equal to 200 grams of TNT, a regional police spokeswoman said. A witness was quoted as saying that he had seen a man placing a black package at the police headquarters gate and then fleeing the scene. A criminal case has been initiated on charges of hooliganism and illegal arms trafficking, police said. A suspicious package was also discovered outside the Interior Ministry Academy in Volgograd, a local police source said. Security forces are checking the site, he said. More that a decade after the end of a federal war against separatists in Russia\'s North Caucasus republic of Chechnya, Russian security forces continue to fight militants in other regions of the North Caucasus, who stage frequent attacks on security forces, police and civilians.