Moscow ? A fire broke out in a women’s ward of a Moscow drug treatment hospital early today, killing 45 women who were trapped by a locked gate and barred windows, officials said.

Russia’s chief fire inspector, Yuri Nenashev, said he was “90 percent certain” the fire was caused by arson. But Moscow city prosecutor Yuri Syomin said investigators were looking into other possibilities, the ITAR-Tass news agency reported.

The fire started in a cabinet in a corridor on the hospital’s second floor – a factor that led to suspicions of arson – and the only possible exit on the floor was blocked by a locked gate, Nenashev said. The barred windows were also locked.

All 45 women were already dead by the time firefighters arrived, said Alexander Chupriyanov, the deputy emergency situations minister.

“Judging by the placement of the bodies, they really tried to get out,” said Alexander Chupriyanov, the deputy emergency situations minister.

About 160 people were evacuated from the five-story Hospital No. 17 in southern Moscow, said Moscow Fire Department spokesman Yevgeny Bobylyov. But he blamed hospital workers for not reacting to the fire sooner and evacuating people more quickly.

Most victims died of asphyxiation, while some died of burns, officials said. Ten people were hospitalized for carbon monoxide poisoning, Bobylyov said. Russian news agencies said two hospital staff members were among the dead.

Nenashev said fire inspectors had visited the hospital twice earlier this year and recommended the temporary closure of the facility because of fire safety violations.

“Unfortunately, this decision was not adopted,” he told reporters at the scene.

Russia records about 18,000 fire deaths a year – roughly 10 times the rate in the United States. Experts say fire fatalities have soared since the collapse of the Soviet Union, in part because of lower public vigilance and a disregard for safety standards.

Reporters were kept well away from the building, which did not have any obvious signs of fire or smoke damage on its facade.

A van from the city’s psychological health service pulled up outside the hospital and a few people went inside, presumably to provide counseling for relatives of the victims. The relatives were brought into the staff entrance to the hospital, well away from reporters.

Bobylyov also criticized hospital officials for not calling the fire department to report the blaze sooner.