Rising equities tend to weigh on gold, which is widely seen as a safe-haven asset compared with higher-risk stocks. Spot gold dropped 0.6 percent at $1,257.53 per ounce by 1:34 p.m. EDT (1734 GMT), having hit its weakest since mid-December at $1,254.16.
US gold futures for August delivery settled down $9, or 0.7 percent, at $1,259.90 per ounce. The dollar rose against its rivals as the escalating concerns of a trade conflict between the world's two biggest economies pushed markets to unwind their bets in high-yielding currencies.
A stronger dollar makes dollar-denominated gold costlier for non-US investors. "The dollar (has been) a lot stronger, that's the main driver here. Also, gold hasn't seemed to benefit from the (trade) turmoil, so I imagine that's made some longs throw in the towel," said Matthew Turner, commodities strategist at Macquarie.
One trader, however, says bullion is being pressured more from speculators and investors abandoning their positions. "Gold is being driven by some capitulation in investors, rather than being primarily driven by the dollar," said Rob Haworth, senior investment strategist for US Bank Wealth Management.
Gold-backed exchange-traded funds tracked by Thomson Reuters were headed for their weakest month since July 2017, as investors covered losses in equities, commodities and other markets caused by tariff disputes. Meanwhile, silver lost 0.3 percent at $16.26 an ounce, slipping to $16.10, its lowest since May 1. Platinum fell 0.3 percent to $867.40 an ounce, while palladium rose 2 percent to $958.25, after having earlier touched its lowest since early April at $929.72.