It was the worst fire in Moscow in three years, prompting emergency response officials to order all health facilities in the city inspected for fire safety compliance.

Fire fatalities in Russia have soared since the collapse of the Soviet Union, and experts say a disregard for safety standards is partly to blame. Russia records about 18,000 fire deaths a year — roughly 10 times the rate in the United States.

Fire inspectors had visited the hospital twice earlier this year and recommended temporarily closing it because of fire safety violations, said Russia's chief fire inspector, Yuri Nenashev.

"Unfortunately this decision was not adopted," he said at the scene of Saturday's blaze.

Nenashev, said he was "90 percent certain" that 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 erupted in a wooden cabinet in a kitchen at one end of a corridor on the hospital's second floor — a factor that led to suspicions of arson — and the only possible exit 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.