LONDON: Copper prices extended their decline on Monday to touch their lowest in almost a week as investors locked in profits amid surging COVID-19 cases and more delays to a US stimulus deal.

Copper tracked a pullback in wider financial markets that were also eyeing the launch of an assembly in China, the world's biggest metals consumer, to agree on the next five-year economic plan.

Three-month copper on the London Metal Exchange was down 0.6% at $6,830 a tonne by 1045 GMT, its third day of losses, after earlier hitting $6,812, its weakest since Oct. 20.

Last week copper broke through the $7,000 level for the first time in 28 months during an online LME Week, as analysts and investors gauged the year ahead for the industrial metals sector.

"It's only natural that there's going to be some profit taking after the euphoria of last week. We're not selling off significantly, there's still a lot of optimism for copper, nickel and tin," said independent consultant Robin Bhar.

"The plenum has kicked off in Beijing so there will be some positive statements in the next few days as we learn more about China's green revolution. This pullback is a good opportunity for people to get some slightly better buying levels."

After a correction, Bhar expects copper to resume its uptrend and move back above $7,000 by the end of the year.

Also pressuring metals was a firmer dollar index, which makes commodities priced in the US currency more expensive for buyers using other currencies.

The global world refined copper market showed a 255,000-tonne deficit in July, compared with a 351,000-tonne deficit in June, the International Copper Study Group said in its latest monthly bulletin.

LME aluminium fell 0.03% to $1,842 a tonne, nickel dropped 1.3% to $15,515, zinc declined 0.7% to $2,541.50, lead slipped 0.3% to $1,781.50 and tin slid 2.9% to $17,875.