London: Copper prices rose on Tuesday as investors bet that top consumer China would respond to weak factory data with stimulus measures and the US dollar weakened, making metals cheaper for buyers with other currencies.
Zinc also gained as surging premiums for cash metal on the London Metal Exchange (LME) pointed to a shortage of nearby supply.
Benchmark LME copper did not trade in official rings but was bid up 0.5% at $6,430 a tonne.
The metal used in power and construction is up around 8% this year on hopes that China can prevent a sharp economic slowdown, but prices have been trapped around $6,500 since late February.
"It is more likely (after the Chinese factory data) that we will see further stimulus measures," said Commerzbank analyst Daniel Briesemann.
He said a likely trade deal between the United States and China would lift copper, but predicted prices would return to $6,500 a tonne at the end of the year.
China factories: Two surveys on Tuesday showed a loss of momentum in Chinese factory activity growth in China in April.
The unexpected slowdown followed upbeat data in March which had raised hopes that the world's largest consumer of metals was getting back on firmer footing.
Trade war: US Treasury Secretary Steven Mnuchin said he hoped to make "substantial progress" with Chinese negotiators in the next two rounds of trade talks.
Euro zone: Euro zone economic growth was stronger than expected in the first quarter, data showed on Tuesday.
Zinc spread: The premium for cash zinc over the three month contract on the LME has leapt to $129, the highest since 1997, suggesting a shortage of immediately available metal.
Zinc stocks: However, zinc stocks in LME-registered warehouses at 81,325 tonnes are up from record lows around 50,000 tonnes earlier this month.
Stockpiles in Shanghai Futures Exchange (ShFE) warehouses at 72,090 tonnes are down from around 124,000 tonnes in March but up sharply from the start of the year.
Zinc price: LME zinc was bid up 0.5% at $2,806 a tonne in official rings, near a 9-1/2 month high of $2,958 reached on 1 April.
Glencore: Glencore cut its target for 2019 copper output to around 1,460,000 tonnes from around 1,540,000 tonnes after a drop in first quarter production.
Chalco: China's Chalco said first-quarter aluminium output fell to 950,000 tonnes from 1.02 million tonnes a year earlier.
Other metals: LME aluminium traded down 0.6% at $1,817 a tonne, nickel was bid 0.2% higher at $12,440, lead was down 0.5% at $1,960 and tin was up 0.2% at $19,700.