Copper prices hit a three-week low on Thursday and other base metals also eased as uncertainty persists over economic conditions and demand growth.

Benchmark copper on the London Metal Exchange (LME) was down 0.7% at $9,462 a metric ton by 0938 GMT after touching it lowest since May 1 at $9,223.20.

"A real state of paralysis has swept through metals markets," said Alastair Munro at broker Marex, pointing to the expiry of LME benchmark contracts last week.

Prices have been pressured by a sharp rise in Chinese copper inventories last week, ending a three-week run of large withdrawals. Analysts and traders said that the rise was due to tepid copper demand in China and steady output from a growing smelting sector.

Also weighing on the market was the prospect of more supply after Freeport Indonesia's Manyar smelter in East Java resumed operations ahead of schedule after a fire last year. It is expected to produce copper cathode by the fourth week of June.

Investor sentiment, meanwhile, remained subdued in the face of a deteriorating U.S. fiscal outlook, with last week's Moody’s downgrade fueling a growing “Sell America” narrative and leaving markets adrift.

Helping to curb losses was a softer U.S. dollar, making dollar-priced metals cheaper for buyers with other currencies.

LME lead fell 1.1% to $1,952 a ton after touching its lowest since May 9 at $1,947.50.

On-warrant LME lead inventories have surged by 91% over the past two days to 234,000 tons, their highest since December 2024.

Among other metals, aluminium dipped 0.2% at $2,467 a ton, zinc eased by 0.2% to $2,688 and nickel was down 0.9% at $15,450 while tin lost 1.4% to $32,365.

(Reporting by Ashitha Shivaprasad in Bengaluru Editing by David Goodman)