US 10-year Treasury yields hit their highest since mid-July on expectations that the Federal Reserve will increase US interest rates for a third time this year, upbeat US data and talk of a possibly more hawkish successor to Fed Chair Janet Yellen.
Rising yields increases the attractiveness of bonds compared to gold while strength in the dollar makes assets priced in the US currency more expensive for buyers holding other currencies.
Spot gold was down 0.3 percent at $1,275.81 an ounce by 1350 GMT, having earlier touched $1,270.60, the lowest in nearly seven weeks. US gold futures for December delivery were down $6.30 at $1,278.50.
The metal posted its biggest monthly fall this year in September despite a quarterly rise of 3 percent, lifted in part by tensions over North Korea's nuclear ambitions.
"The recent sell-off is mostly related to a stirring of the reflation trade following the announcement by the Trump administration of the long-awaited tax reform proposal," Mitsubishi analyst Jonathan Butler said.
"The dollar has jumped to six-week highs, Treasury yields have surged to three-month highs as investors search out risk assets and US equities reached new record highs on Friday."
The euro also came under pressure after Spanish police used batons and rubber bullets in an effort to thwart an independence vote in Catalonia on Sunday, leaving hundreds injured. The single currency was down 0.6 percent versus the dollar.
With European bourses opening higher, gold failed to benefit from increased demand for havens from risk.
Speculators cut their net long positions in COMEX gold and silver contracts in the week to Sept. 26, US data showed on Friday.