Sixteen people were killed and one person was missing after a fire broke out at a Russian explosives factory southeast of Moscow on Friday, local authorities said.
The blaze took place in the village of Lesnoy, 300 kilometres (185 miles) from the capital in the region of Ryazan.
Authorities originally said 15 people had died, but later said one man who received severe burns had died in hospital.
"The fate of one more person is unknown," the local government said on its website, adding that rescuers were "looking for him".
Seventeen people were believed to have been inside the plant's workshop at the time of the fire.
Images released by authorities showed firefighters working their way through the debris at the severely damaged factory building.
The plant is considered a "strategic company" by the Russian government. According to its website, it produces explosives civilian and military use.
Russia's emergencies ministry said the fire could have broken out as a result of "violations of technological processes and safety measures" at the PGUP Elastic factory.
Detectives were dispatched to the village to probe if the factory had complied with "industrial safety" standards, said the Investigative Committee, which probes major crimes in Russia.
The blaze is the latest deadly accidental fire in Russia, where non-compliance with safety standards -- that are already lax -- is common.
The acting head of the emergencies ministry, Alexander Chupriyan, arrived at the site by helicopter.
He took charge of the ministry after its chief Yevgeny Zinichev died falling off a cliff during Arctic exercises last month.
Firefighters first received a report that a fire had broken out at the plant at 08:22 am local time, the emergencies ministry said.