Copper fell to five-months lows, posting its biggest two-day loss since July 2015, on rising inventories and worries over cooling demand.
Inventories in London Metal Exchange (LME) warehouses rose nearly 33,000 tonnes on Wednesday, exchange data showed, bringing this week's increase to 64,000 tonnes, or 25 per cent.
That followed data this week showing that US factory activity slowed in April while growth in China's manufacturing sector slowed more than expected.
A report overnight showed that new orders for goods manufactured in the United States rose for a fourth month in March, but by less than expected.
"We're seeing weaker manufacturing data this week, especially in China and the US, which is affecting base metals negatively, and I sense the market is starting to lose patience with the lack of progress on (US President) Trump's infrastructure spending plans," Danske Bank analyst Jens Pedersen said.
"Producers have been caught off guard by this slowdown in the industrial cycle, and therefore are having to place (metal) in inventories."
LME copper closed 1 per cent down at $US5543 a tonne, having touched $US5494, its lowest since January 4. Prices registered their biggest one-day drop since September 2015 in the previous session, falling 3.5 per cent.
A break of support at $US5563 a tonne in LME copper prices could trigger a loss into the range of $US5433-$US5508, Reuters technical analyst Wang Tao said.
LME copper stocks
The Philippine government will move forward with a second review of the country's mines despite the removal of Regina Lopez as environment minister, a finance official said on Thursday. Lopez will no longer be in a position to suspend about 8 per cent of global nickel supply, Goldman Sachs said in a note.
LME nickel closed 2.3 per cent down at $US9015 a tonne, off an earlier 10-month low of $US8970.
Mining and trading group Glencore has hired the Bank of Nova Scotia to sell a portfolio of royalty assets, including one for the Antamina copper-zinc mine in Peru, four people familiar with the process told Reuters.
One company was holding more than 90 per cent of lead warrants and cash contracts. Cancelled warrants, or material earmarked for delivery and unavailable to the market, made up nearly half of total inventories.
LME lead finished 0.5 per cent lower at $US2190 a tonne, while zinc closed 0.2 per cent down at $US2569. Aluminium ended with a 0.6 per cent decline at $US1913.