Copper futures in New York slipped over 2 percent at the open on Tuesday, pressured by another large influx of stocks into London warehouses and a slightly weaker base metals complex, sources said.
"The big increase in London Metal Exchange stocks is a part of the weakness this morning and we're seeing some profit-taking in some of your other base metals that have been leaders of late," said James Quinn, commodity commentator with A.G. Edwards.
By 10:05 am EDT (1405 GMT), copper for December delivery was off 7.85 cents, or 2.27 percent, at $3.3725 a lb on the New York Mercantile Exchange's COMEX division, dealing from an eight-day low of $3.35 to $3.4630.
Quinn pegged short-term support in December copper around the $3.33 level, followed by $3.30. Spot October fell 8.00 cents to its morning low at $3.35. COMEX copper volume at 9:00 am was estimated at 2,000 lots.
Inventory data showed London Metal Exchange-monitored warehouse stocks jumped 7,750 tonnes, or 6.8 percent, to 120,825 tonnes on Tuesday, while COMEX stocks rose 184 short tons to 22,651 tons on Monday.