Tokyo, July 31 (Jiji Press)--The dollar tumbled below 160.50 yen in Tokyo trading Friday morning amid speculation that the Japanese government and the Bank of Japan conducted yen-buying, dollar-selling intervention in the foreign exchange market. Reports that the Federal Reserve Bank of New York conducted a rate check, widely viewed as a precursor to market intervention, also added downward pressure on the dollar, market sources said. At 9 a.m., the dollar stood at 160.17-18, down from 163.72-73 yen at 5 p.m. on Thursday. In overseas trading the previous day, the dollar moved sideways around 163.60 yen during European trading hours. However, once U.S. trading began, the dollar suddenly tumbled below 158 yen to hit the lowest level since mid-May. "It appears that the Japanese government and the BOJ intervened" in the market, a Japanese bank official said. The U.S. currency later recovered to levels above 159.80 yen, but then fell sharply again to around 158.50 yen. Toward the end of U.S. trading hours, the greenback regained some ground, rising back to around 159.40 yen. In early Tokyo trading, the dollar initially hovered around 159.70 yen before continuing its rebound. "Concerns about further market intervention remain strong," a major Japanese bank official said. Meanwhile, an FX brokerage firm official said, "Expectations for a weaker yen have not changed, making dollar buying on dips likely to continue." END [Copyright The Jiji Press, Ltd.]