The base metal prices on the London Metal Exchange (LME) closed lower mostly on Monday.
The U.S. dollar index, which measures the greenback against a basket of six major currencies, exceeded 90 again on Monday. The strong U.S. dollar weighed on base metal prices.
"Copper faces pressure from weak demand and a strong U.S. dollar. Given the lack of positive news, we believe that LME copper may fall further and test the 6,260 U.S. dollars level last struck in March," Capital Futures said in a report.
The three-month unofficial copper price dropped 54.25 U.S. dollars, or 0.86 percent, to 6,265 U.S. dollars per tonne.
The three-month unofficial aluminium price increased 1.25 U.S. dollars, or 0.07 percent, to 1,865 U.S. dollars a tonne.
The three-month unofficial lead price lost 11.5 U.S. dollars, or 0.62 percent, to 1,842.5 U.S. dollars a tonne.
Besides, the three-month unofficial zinc price lost 11.75 U.S. dollars, or 0.54 percent, to 2,146 U.S. dollars a tonne.
The three-month unofficial nickel price lost 220 U.S. dollars, or 1.44 percent, to 15,087.5 U.S. dollars a tonne.
The three-month unofficial tin price increased 277.5 U.S. dollars, or 1.48 percent, to 19,025 U.S. dollars a tonne.