Russian stocks posted sharp losses Thursday on fears the country's economy is being hit particularly hard by the global financial crisis and the continued fall in crude oil prices. The MICEX, where most of Russia's trading takes places, lost 10 percent in the first 30 minutes after opening, down to 583 points. The other main exchange, RTS, slipped 4.2 percent to 608.2 points. Troubled fertilizer producer Uralkali dropped 25.3 percent and mining giant Norilsk Nickel fell 21.6 percent. Russia's largest oil producer Rosneft lost almost 20 percent. Regulators have repeatedly suspended trading on the two exchanges in recent days as shares bounced up and down.