Bullion is still down by more than a fifth since the US-Iran war erupted in late February. (EPA images pic)SINGAPORE: Gold extended gains -- after jumping more than 3% on Wednesday -- as a Democratic sweep of Congress in the US midterm elections sent the dollar and Treasury yields lower.

Bullion rose as much as 1.9% to trade near US$4,140 an ounce, after rising the most since August in the previous session to back above the US$4,000 support threshold.

Treasury yields fell across the curve on Wednesday and the dollar weakened 0.4% on the election result, which delivered a sharp rebuke of the Trump administration. Both the greenback and yields dropped further on Thursday.

Lower yields tend to support gold as it doesn’t pay interest, while a weaker dollar makes the precious metal cheaper for buyers in other currencies.