TOKYO, Aug 17 (Reuters) - Japanese government bond yields declined on Tuesday, in line with moves in Treasuries, as investors awaited further clues on the timeframe for tightening U.S. monetary policy. The 10-year JGB yield fell 0.5 basis point to 0.005%, as yields on equivalent-maturity Treasury notes sank 3 basis points in Asian trading to 1.2367%, extending a 1-1/2 basis point slide from Monday. Benchmark 10-year JGB futures rose 0.03 point to 152.39, with a trading volume of 11,950 lots. The two- and five-year yields fell 0.5 basis point each to minus 0.145% and minus 0.135%, respectively. Twenty-year yields were flat at 0.395%, while the 30-year yield eased 0.5 basis point to 0.635%. Trading was thinned by the Obon holiday which ran to Monday, with no auctions or Bank of Japan operations on Tuesday to offer the market direction. Federal Reserve watchers remain focused on its Jackson Hole, Wyoming annual symposium from Aug. 26, while Chair Jerome Powell speaks later Tuesday and minutes of the Fed’s latest policy meeting are released on Wednesday. “Generally speaking, it’s still the case that most investors want to wait and see what comes out of the Jackson Hole meeting next week,” said Makoto Suzuki, senior bond strategist at Okasan Securities. “There are no market participants wqho are moving actively to invest now.” (Reporting by Tokyo markets team; Editing by Krishna Chandra Eluri) Our Standards: The Thomson Reuters Trust Principles.