(Updates prices for Asia market close)

SHANGHAI, March 19 (Reuters) - Copper prices on the

London Metals Exchange (LME) held firm near a five-month high on

Wednesday, with markets watching out for potential U.S. tariffs

on copper.

Benchmark three-month copper on the LME was up 0.2%

to $9,923 a metric ton as of 0723 GMT. Prices hit a 5-month

intraday high of $9,937 on Wednesday.

Earlier, U.S. President Donald Trump had ordered a probe

into possible new tariffs on copper, inflating the premium of

Comex copper over the LME contract, which was at a record high

of $1,192 a ton on Tuesday.

"Trump's potential tariff on copper is what we are watching

closely now and the premium of Comex copper over LME copper

continues to broaden, with the market speculating about a

potential 25% tariff on copper by Trump," a trader said.

Meanwhile, the head of Russian metals and mining giant

Nornickel, Vladimir Potanin, said on Tuesday that he

expects updates on a Chinese copper-producing joint venture in

the coming months.

Nornickel is in talks for a joint venture in China, with

potential investments in early financial plans for 2025-2026.

LME aluminium rose 0.1% to $2,657 a ton, lead

was unchanged at $2,095, zinc lost 0.2% to $2,958.5 and

tin remained flat at $35,420. Nickel gained 1.1%

to $16,425.

SHFE copper climbed 0.7% to 80,890 yuan a ton, SHFE

aluminium dropped 0.6% to 20,705 yuan a ton, zinc

slid 0.2% to 23,895 yuan, lead gained 0.6% to

17,690 yuan and nickel gained 0.7% to 131,660 yuan. Tin

gained 0.4% to 281,780 yuan.