The International Monetary Fund (IMF) cut its forecast for world economic growth this year to 3.3 percent from 3.5 percent previously, citing the US-China trade war and a potentially disorderly British exit from the European Union.
It warned chances of further cuts to the outlook were high.
The US Trade Representative on Monday proposed to slap tariffs on a list of European Union products ranging from large commercial aircraft to dairy products and wine as it kicked off the retaliation process against European aircraft subsidies.
FUNDAMENTALS
Three-month copper on the London Metal Exchange dipped 0.1 percent to $6,483 a tonne by 0137 GMT, snapping two days of gains, while the most-traded copper contract on the Shanghai Futures Exchange was little changed at 49,610 yuan ($7,386) a tonne.
Other metals were mixed, with London aluminium edging up 0.1 percent and lead rising 0.3 percent. Shanghai zinc was on track for its third straight decline, down 1 percent, while lead fell 0.8 percent.
An indigenous community in Peru voted to suspend its two-month road blockade of MMG Ltd's Las Bambas copper mine for two days until the government visits the region on Thursday, an advisor to the community told Reuters.