Three-month copper on the London Metal Exchange closed at $9,510 a tonne, down from Thursday's close of $9,565.
China's central bank raised lenders' required reserves for the sixth time in a cycle of monetary tightening.
"This is definitely taking the sheen off the market," said Standard Bank analyst Stephen Reece. "The fact that this is the sixth time that China's bank intervenes is more important than the fact that it is a 0.50 point increase only."
But some said the impact of Chinese tightening measures would be moderate in the longer term.
"China is taking some moderate measures to cool down the economy. This may have a negative impact in the near term, but we don't think it will derail China's growth in terms of base metals," Credit Suisse analyst Stefan Graber said. "China's metals demand will continue to grow robustly this year."
News that Libya declared a ceasefire in the country to comply with a United Nations resolution passed overnight boosted market confidence.
"The ceasefire in Libya provided some sort of support to the market and certainly there has been a lift," said Daniel Major, an analyst at RBS. "In the near term less military action is always taken as positive.
Earlier, the Group of Seven agreed on joint intervention to curb the soaring yen and calm markets over Japan's nuclear power plant crisis.
"There is a rebound in risk appetite, but it's being limited by what is going on in the Middle East," Danske Bank analyst Christin Tuxen said.