A female bomber blew up a bus carrying workers from a Russian air base near Chechnya on Thursday, killing herself and at least 14 people and injuring many others, officials said. The bus was traveling from the city of Mozdok in the North Ossetia region to a nearby military air base and was waiting at a closed railroad crossing when a woman in a white medical coat stepped aboard and detonated explosives, a regional Interior Ministry official said. Six people were killed at the scene and nine others died in a hospital, the official said. He said there were more than 40 people on the bus and that all were wounded, many seriously. The passengers included an air crew and support workers from the Prokhladny air base, said North Ossetia's emergency situations minister, Boris Dzgoyev. He said they were members of 4th Air Army, which serves southern Russia and is based in the city of Rostov-on-Don. Dzgoyev said there were at least 27 people aboard the bus, including 14 women. He also said that at least 15 people were killed, including the attacker, and that 12 people were hospitalized, three of them in grave condition. Air Force spokesman Alexander Drobyshevsky said the 15 dead included eight servicemen and seven civilians working at the air base, the Interfax news agency reported. He did not mention the attacker. Mozdok is the main headquarters for Russian forces who have been fighting Chechen fighters. Fierce fighting and rebel attacks have persisted despite efforts by the Kremlin and the Moscow-backed government in Chechnya to bring stability and peace. Two bomb attacks in a three-day period inside Chechnya last month killed at least 78 people, and there are frequent attacks on buses and other occupation military vehicles in the region. There are rules in place barring military buses from picking up passengers for fear of terrorist attacks, the regional Interior Ministry official said. However, officials said the attacker had still managed to board the bus. **PHOTO CAPTION*** Rescue workers looking for survivors after an explosion destroyed a pro-Russia government building in Chechnya. (Archive, AFP/NTV/File)