China, which accounts for about half of all metals demand, imported 4.7% more copper in January-February despite a recent spike in prices while exports grew at a record pace.
Benchmark three-month copper on the London Metal Exchange (LME) rose 0.5% to $8,851 a tonne.
The metal is mainly used in stainless steel, but demand for battery grade nickel for electric vehicles is expected to boom in as the world moves towards a lower-carbon economy.
Benchmark three-month nickel edged up 1.5% to $16,379 a tonne in official trading but was still on track for a weekly loss of about 11%, its biggest since September 2011.
Benchmark copper on the London Metal Exchange (LME), which hit a 10-year high of $9,617 a tonne last week, was on track for its worst day since October as it lost 4.2% to $8,720.
Nickel, meanwhile, tumbled for a second day. Having reached a seven-year high of $20,110 last week, it traded at $16,175 a tonne, down 7.1% and set for its biggest one-day loss since 2016.
Benchmark copper on the London Metal Exchange (LME) was up 1.2% at $9,150 a tonne.
On the Shanghai Futures Exchange (ShFE), speculators' net long reached 57.9% of open contracts on Friday, the most since 2003, before falling to 51.8% on Monday, Marex said.
The last warehouse company to be approved by the LME was Edgemere Terminals in August 2018, the LME said.
LME-registered warehouses also issue LME warrants, or title documents, through their London agents for material delivered into their approved warehouses.