[url]http://www.foxnews.com/story/0,2933,88623,00.html[/url]

VLADIKAVKAZ, Russia  — A female homicide attacker blew up a bus carrying personnel from a Russian military air base near Chechnya on Thursday, killing at least 15 people in a new blow to the Kremlin's claims of increasing stability in the region.

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 railroad crossing when a woman in a white coat -- the usual uniform for medical personnel -- 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. Russian news reports said the blast shattered windows near the site.

The passengers included an air crew and support workers from the Prokhladny air base three miles from Mozdok, 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.

Alexander Koval, a Russian military spokesman in the North Ossetian capital Vladikavkaz, said the attack killed the homicide bomber and 17 other people, 14 of them women.

Russian Deputy Prosecutor General Sergei Fridinsky said 16 people were killed and gave a different location for the attack, saying it happened not at a railroad crossing but at the final stop on the bus's route from Mozdok to the base.

Fridinsky, speaking at a news conference in Rostov-on-Don, said the attacker did not get on the bus but instead blew herself up outside the vehicle. North Ossetian Prime Minister Mikhail Shatalov said the woman thrust herself under the bus before detonating the explosives, the Interfax news agency reported.

There are rules in place barring military vehicles from picking up passengers for fear of terrorist attacks, the regional Interior Ministry official said.

Fridinsky said it appeared the attacker had intended to reach the air base outside Mozdok. The city 80 miles northwest of the Chechen capital Grozny is the main headquarters for Russian forces who have been fighting rebels in Chechnya for most of the past decade.

Fierce fighting and rebel attacks have persisted despite steps by the Kremlin and the Moscow-backed government in Chechnya to boost stability.

Two homicide bombings in a three-day period inside Chechnya last month killed at least 78 people, and there are frequent attacks on buses and other military vehicles in the region.

The attacker's identity was unknown. Among Chechen rebels, homicide attacks by women are an increasingly common tactic. A woman blew herself up at a religious ceremony in Chechnya on May 14, killing at least 18 people, and women draped with explosives took part in the hostage-taking raid on a Moscow theater last October.

Russia has been trying to end a separatist rebellion in Chechnya for most of the last decade. Russian forces left Chechnya in 1996 after 20 months of fighting bogged down into a violent stalemate.

They returned in 1999 after Chechnya-based insurgents made raids into neighboring Dagestan and after some 300 people died in apartment bombings that Russian officials blamed on the rebels.