(Updates prices, adds comment from traders, changes dateline to

London)

By Polina Devitt

LONDON, April 22 (Reuters) - Copper prices rose on

Wednesday amid cautious optimism over U.S.-Iran peace talks

after President Donald Trump said he would indefinitely extend

the ceasefire, while inflows to U.S. copper stocks continued

amid a sustained price premium.

The benchmark three-month copper on the London Metal

Exchange was up 0.7% at $13,314.50 a metric ton as of 0852 GMT.

The renewed premium of Comex copper prices over the

LME global benchmark, a defining feature of the copper market in

2025, has re-emerged this month, encouraging shipments to the

United States.

Copper stocks in Comex warehouses are up 2%

since mid-April at 544,887 metric tons, nearing a record high of

545,867 tons set in February. Meanwhile, inventories in the LME

system stood at 395,575 tons after recent outflows from

LME-registered warehouses in Asia.

More copper will flow to the U.S. while the price premium

persists until July, when a decision is expected on whether to

impose tariffs on the metal, said Kostas Bintas, the global head

of metals at trade house Mercuria.

At the Financial Times Commodities Global Summit in

Lausanne, Switzerland, market participants were largely bullish

on copper in the long term, but they pointed out near-term

demand risks in the case of a prolonged conflict in the Middle

East.

Meanwhile, the global aluminium market is already

experiencing a "black swan" supply shock due to disruptions

stemming from the war, which is expected to result in major

shortages this year, according to a top metals analyst at

Mercuria.

LME aluminium was last up 1.4% at $3,606 a ton. The

contract hit a four-year high at $3,672 on April 16.

Among other LME metals, zinc added 0.4% to $3,457,

lead fell 0.4% to $1,956, tin gained 1.4% to

$50,505 and nickel rose 1.2% to $18,445.