The Shanghai Futures Exchange will be shut from the night trading session on Tuesday, reopening next Monday. China is the world's top metals consumer.
The U.S. economy accelerated more than expected in the first quarter, putting to rest fears of a recession. But there was caution over less upbeat aspects of a GDP report which pointed to some weakening ahead.
FUNDAMENTALS
* Three-month copper on the London Metal Exchange had fallen 0.2 percent to $6,385 a tonne by 0154 GMT, while the most-traded copper contract on the Shanghai Futures Exchange was almost flat at 48,870 yuan ($7,256.34) a tonne.
* Profits at China's industrial firms grew in March, rebounding from four months of contraction, adding to optimism the world's second-largest economy may be starting to stabilise.
* U.S. President Donald Trump on Friday said trade talks with China were going very well, as the two countries seek to end talks with a trade agreement to defuse tensions.
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MARKETS NEWS
* Asian stock markets inched up after the U.S. first-quarter economic growth data boosted the S&P 500 index to a record-high.