Benchmark copper on the London Metal Exchange (LME) rose 0.3pc to $5,872 a tonne at 0414 GMT, but was down 8.5pc for the month of May, the strongest monthly decline in three-and-a-half years.
The metal has fallen 9.8pc in the past three months.
Disruptions in top copper producer Chile, political and power problems in Zambia and restrictions on scrap imports into China are expected to weigh on copper supplies and likely lead to a tighter market in the second half of 2019.
Chile's Codelco, the world's top copper miner, reported an 18pc year-on-year drop in its first-quarter copper output on Thursday to just 342,000 tonnes, and its pre-tax profit fell 31pc to $372 million from the same period in 2018.
US President Donald Trump on Thursday stoked global recession fears by slapping a 5pc tariff on all goods from Mexico from June 10 until illegal immigration is stopped.
The tariff would gradually increase to 25pc by Oct. 1.
Chinese data released on Friday showed a disappointing performance in the manufacturing sector in May, adding to pressure on Beijing to roll out stimulus measures to support its economy hit by a trade war with the United States.
"We expect (the Chinese) government will continue to adopt many stimulus tools available to protect the economy, including further monetary easing such as reserve requirement ratios cuts and fiscal stimulus," said analyst Helen Lau of Argonaut Securities in a note.
FUNDAMENTALS
LME: Three-month aluminium in London rose 0.2pc, nickel fell 0.8pc, zinc dropped 0.8pc and lead declined 0.4pc.
SHFE: In Shanghai, copper fell 0.3pc to 46,470 yuan ($6,725.91) a tonne, aluminium was almost flat, nickel rose 0.1pc and zinc eased 0.2pc.
ZAMBIA COPPER: Zambia says its decision to punish miner Vedanta's local operation for breaching environmental and financial regulations is a signal to other firms to follow the law, mines minister Richard Musukwa said on Thursday.
NICKEL: The Philippines' nickel ore production in the first quarter rose 3pc from a year earlier to 2.97 million dry metric tonnes, despite zero output from more than half of the country's 28 mines, the government said on Thursday.