Credit rating agency Standard & Poor's said on Wednesday it had upgraded Russia's long-term local and foreign currency sovereign credit ratings B+ from B, revising its rating outlook to stable from positive. It also affirmed Russia's B short-term sovereign credit rating. S&P said in a statement that the upgrade reflected almost one year of improvement in Russia's policy environment, which has strengthened the country's economic structure and bolstered economic prospects and policy flexibility. "As a result, the economy is becoming less dependant upon and vulnerable to the vagaries of the oil market in the current uncertain international environment," the agency said. Stronger than expected economic growth had been underpinned by a strong reform momentum, including judicial reform, beginning in May, S&P said. Russia is rated an equivalent B+ by rival credit rating agency Fitch, and a slightly higher Ba3 by Moody's Investors Service, the Russia Journal reported.