Workers at one of Russia's biggest aluminum smelters say their Siberian town is doomed unless Moscow mitigates U.S. sanctions against aluminum giant Rusal, a predicament mirrored across the company's sprawling operations.

Trapped by mortgages for apartments built on barren steppe under communism, residents of Sayanogorsk, one of a string of towns dominated by Rusal, have few options if a loss of customers for its aluminum leads the firm to cut jobs.

"The entire life of this city depends on Rusal," said Evgeny Ivanov, until recently a foreman at the plant in Sayanogorsk, where pockmarked asphalt recalls the harsh winters endured by its 60,000 inhabitants, and icy blue mountains line the horizon.