LONDON: Copper prices hit their lowest level in almost three weeks on Wednesday due to a stronger dollar and an uncertain American election that dampened hopes of large US stimulus and infrastructure spending.

President Donald Trump falsely claimed victory over Democratic rival Joe Biden, but the outcome of the US presidential race was not expected to be decided until tallying is completed over the coming hours or days.

Three-month copper on the London Metal Exchange was down 1.3% at $6,726 a tonne by 1115 GMT after touching $6,670, the weakest since Oct. 15.

Copper has rebounded 54% since March, bolstered by a strong recovery from the COVID-19 pandemic in top metals consumer China.

"Biden was widely expected to throw a lot of money into the system," said Ole Hansen, head of commodity strategy at Saxo Bank in Copenhagen.

"A change to a Democratic White House would mean they would come out all guns blazing trying to achieve something in the first 100 days, but that's potentially not going to happen, especially if they don't get a Senate majority."

Republican incumbents were largely holding off Democratic challengers for control of the US Senate.

The dollar index rose, making metals priced in the US currency more expensive for buyers using other currencies.

Helping to curb losses in copper was news that a union of workers at Chile's Candelaria copper mine had rejected yet another contract offer from the company and would push forward with a nearly month-long strike that has shut down the mine.

China's Lygend Resources & Technology Co Ltd will not begin operating a nickel smelter at a project planned for eastern Indonesia until March 2021, a six-month delay.

Aluminium dropped 2.4% to $1,859 a tonne, zinc declined 1% to $2,541.50 while lead rose 0.1% to $1812.50.

Nickel lost 1.2% to $15,185 after touching $14,930, the lowest since Oct. 9, and tin slipped 0.4% to $17,995.