The victims are "Vietnamese citizens," the ministry's statement said. Russian news agencies quoted local sources as saying the migrants were employed illegally to work in a sewing factory.
Russian investigators launched a probe into possible violation of fire safety regulations, the Investigative Committee said in a statement. "There were no signs of a violent death," the statement said.
Investigators and police were inspecting the area around the brick building that formerly housed a cotton factory, and trying to identify the dead bodies, it said.
Migrant workers in Russia often work illegally in squalid conditions which endanger their health and lives. In April, several migrant workers died in a fire at a Moscow market, where they also lived.
A source in the police told Life News website that the workers in Yegoryevsk were locked from the outside by their employers to sow clothing in the small room and were only brought food and materials once a day.
Immigration officers and police in the town raided a covert factory making children's clothing on August 2 finding 150 Vietnamese migrants, local administration said on its website last month.
In another widely reported recent case, a local police colonel was accused of keeping illegal migrant workers at his farm, where they worked for free after their documents were taken away.
Russia estimates that up to five million migrant workers are in Russia illegally, although figures are hard to establish. Cheap labor from Central Asia is often used in construction and manual labor, causing a rise of xenophobic attitudes over the past decade.
The World Bank said in its latest migration report that migrant remittances from Russia amounted to $18.7 billion in 2010, making it one of the biggest destination countries in the world for migrants.
