LONDON - Copper prices retreated on Tuesday as weak manufacturing data indicated poor demand prospects, including from top consumer China,though falling inventories suggested a tighter market.

Benchmark copper CMCU3 on the London Metal Exchange (LME) was down 0.5% to $8 356 a metric ton at 10:06 GMT. Prices of the industrial metal hit a four-week low of $8 141 a ton last week.

Surveys of purchasing managers in China's manufacturing sector suggest that the world's second-largest economy lost momentum in the second quarter as demand weakened.

In the euro zone and United States manufacturing activity slumped in June to levels last seen when the global economy was reeling from the initial wave of the Covid-19 pandemic and lockdowns.

"Macro headwinds around the world and stuttering growth in China continue to weigh," a metals trader said. "It's difficult to tell at this stage where the trigger for buying or selling will come from."

Traders also expected subdued volumes on Tuesday due to a US holiday.

Copper stocks in LME-registered warehouses have dropped 33% since June 6 to 66 775 tons, while cancelled warrants -- metal earmarked for delivery -- sit at 46% of the total, indicating more metal is due to leave the LME system MCUSTX-TOTAL.

Stocks of copper in warehouses monitored by the Shanghai Futures exchange have fallen 73% since late February to 68,313 tonnes CU-STX-SGH.

Meanwhile, a closely watched indicator of China's copper import appetite, the Yangshan copper premium SMM-CUYP-CN, has more than doubled since the middle of May to $50 a ton.

"Our current forecast is for global refined copper demand growth of 1.8% this year, with China growing at a robust 3.3%, higher than previously expected due to strong power investment, electric vehicles and increased consumer spending," Macquarie analysts said in a note.

In other metals, aluminium CMAL3 slipped 0.1% to $2 155 a ton, zinc CMZN3 gained 0.3% to $2 372, lead CMPB3 was little changed at $2 091, tin CMSN3 fell 0.3% to $27 280 and nickel CMNI3 retreated 0.4% to $20 500.