* GRAPHIC-2019 asset returns: http://tmsnrt.rs/2jvdmXl
* Premium for cash zinc over 3-month hits 3-month high (Updates prices)
LONDON, Sept 30 (Reuters) - Copper held steady on Monday as above-consensus industrial activity data from top consumer China supported prices, but weak demand due to the prolonged U.S.-China trade war weighed on sentiment.
Benchmark copper on the London Metal Exchange was untraded in official rings, and was last bid down 0.1% at $5,759 a tonne. Prices of the metal widely used in power and construction last week touched $5,711, their lowest since Sept. 4.
"The surprisingly positive China PMI data is giving some support to prices of copper and other metals, but it might be short-lived," said Commerzbank analyst Daniel Briesemann.
"The market is waiting for trade talks. We don't expect much activity before then due to celebrations in China (to mark 70 years of Communist Party rule)."
PMIs: The Caixin/Markit Manufacturing Purchasing Managers' Index (PMI) for September rose to 51.4 from 50.4 in August. The consensus was for a dip to 50.2.
Another official survey showed factory activity picked up in September on improving domestic demand, despite shrinking for the fifth straight month as new export orders continued to fall.
The official PMI was at 49.8 in September, slightly higher than 49.5 in August.
"The official survey is a mix of large state-owned enterprises and private companies... while the Caixin puts more emphasis on smaller and private companies," said analyst Helen Lau of Argonaut Securities.
CHINA: China accounts for nearly half of global copper demand, estimated at 24 million tonnes this year.
TRADE: China hopes Beijing and Washington will resolve their trade dispute "with a calm and rational attitude," Vice Commerce Minister Wang Shouwen said on Sunday, ahead of talks expected in Washington on Oct. 10-11.
The United States and China have been locked in an escalating trade war for over a year. They have levied punitive duties on hundreds of billions of dollars of each other's goods, roiling financial markets and threatening global growth.
STIMULUS: China plans to step up economic adjustments to counter its slowing economy while providing adequate liquidity in the economy, the central bank said on Sunday.
HOLIDAY: The Shanghai Futures Exchange (ShFE) will be closed during Oct. 1-7 for the National Day holiday.
ZINC: The premium for the cash over the three-month contract soared to a three-month high of $50 a tonne <MZN0-3> due to worries about supplies on the LME market.
These worries have been fueled by one company holding large amounts of cash contracts, and stocks in LME warehouses near historical lows at 67,300 tonnes <MZNSTX-TOTAL>.
Three-month zinc was up 0.8% at $2,322 a tonne.
PRICES: Aluminium traded down 0.5% at $1,722, lead rose 1.1% to $2,093, tin slipped 0.3% to $16,075 and nickel added 1.0% to $17,375 a tonne. (Reporting by Pratima Desai; additional reporting by Mai Nguyen; editing by Emelia Sithole-Matarise and Jan Harvey)