Firefighters put out a "huge" fire on Sunday at Russian steelmaker MMK, in the city of Magnitogorsk in the south Ural mountains, the emergencies ministry said.
It said the plant's conveyor belt caught fire at around 0900 (0400 GMT). No one was hurt in the incident, whose cause was being investigated. The stoppage had no impact on production.
The company, controlled by Russian businessman Viktor Rashnikov, said last week it expected first-quarter sales of finished products to remain under pressure from weak seasonal demand amid low global prices.
(Reporting by Vladimir Soldatkin; editing by John Stonestreet).