TOKYO, Sept 7 (Reuters) - Japanese government bond prices slipped on Thursday as a retreat by U.S. Treasuries and a subdued 30-year debt auction weighed on the market.
The benchmark 10-year JGB yield rose 1 basis point to 0.015 percent, its highest in 10 days. The yield had declined to a 10-month low of minus 0.010 percent on Monday when geopolitical concerns gripped the broader markets.
The 20-year yield was up 2 basis points at 0.540 percent and the 30-year yield was up 2 basis points at 0.825 percent.
Super-long JGBs underperformed slightly following Thursday's 30-year auction.
The bid-to-cover ratio, a gauge of demand, at the 800 billion yen ($7.34 billion) 30-year sale slipped to 3.67 from 3.90 at the previous auction in August.
The 30-year yield had dropped to a 2-1/2-month trough of 0.800 percent at the start of the week, and the low yields were seen to have discouraged some potential buyers at Thursday's auction.
U.S. Treasury prices fell on Wednesday as a congressional fiscal plan that includes a three-month suspension of the debt ceiling gained support from President Donald Trump, reducing safe-haven demand among investors worried about a short-term default. ($1 = 109.0300 yen) (Reporting by the Tokyo markets team; Editing by Sunil Nair)