Copper dropped to its lowest level in a month as Europe's debt crisis hit investor confidence.
"The dollar is rebounding strongly against the euro, which is putting base metals under pressure. Markets are worried about the prospects for global growth and no new step to help contain the euro-zone crisis," said Dan Smith, the head of metals research at Standard Chartered in London.
"There is a lot of option trading activity in copper at the moment."
The three-month contract on the London Metal Exchange (LME) retreated as much as 2.3 per cent to US$8,500 a tonne, the lowest price since August 9. Copper has lost 4.2 per cent in the past two weeks, after a 5.7 per cent drop last month.
China is the largest buyer of the metal, which gained 27 per cent last year.
Five cable companies are listed in the Middle East and North Africa, and the price decline could help their profit margins.
European finance chiefs last week said the debt crisis left no room for tax cuts or extra spending to improve the region's economy. They also pushed back to next month a decision on whether Greece should receive another bailout.
The price of the metal had been supported earlier by strikes at Freeport-McMoRan Copper & Gold mines in Indonesia and Peru.
But 1,500 workers returned to the mines in Indonesia this weekend, which helped bring prices lower. Indonesia has the world's third-biggest copper mine.
Warehoused copper inventories monitored by the London Metal Exchange rose 0.7 per cent to 469,125 tonnes, the most since July 27.
Nickel for three-month delivery on the LME declined 1.3 per cent, zinc fell 2.6 per cent, aluminium lost 1 per cent, lead slid 0.8 per cent and tin fell 2.1 per cent.