MOSCOW, Aug 8 (Reuters) – Russian aluminium giant Rusal is concerned about an impending catastrophe if U.S. sanctions are not lifted, with some of its production halted as early as September, two sources close to the company said. Under the terms of the sanctions, imposed in April in response to Moscow’s alleged meddling in the 2016 U.S. election, U.S. customers must wind down business with Rusal by Oct. 23. “If sanctions are not lifted in the near future, then contracts will expire and from Oct. 1, all of the company’s production, intended for the external market, will once again go into the warehouses,” a source close to Rusal said. “Considering that before the sanctions were introduced, Rusal sold around 80 percent of its output for export, the situation could be catastrophic not only for all the company’s plants around the world, but also for the global aluminium market,” the source said. Rusal declined to comment. On Tuesday the company said it was putting a halt to production at its small Nadvoitsky plant as a result of the sanctions, since all of its output was geared to the U.S. market.