MOSCOW, Jan 19 (Reuters) - The Russian central bank said on Wednesday that the risk of inflation deviating further upwards from its 4.0% target remained significant but that it still planned to bring inflation down to 4.0%-4.5% by the end of the year. The bank, which said that risks of external inflationary pressure remained high, said volatility in the rouble exchange rate could accelerate inflation in the short term. Volatility has plagued the Russian market in the last few trading sessions amid a standoff with the West over Ukraine. Annual inflation stood at 8.4% last month, according to the central bank.