Updates with official prices

By Polina Devitt

LONDON, Nov 19 (Reuters) - Base metals prices came under pressure on Tuesday as some investors chose safe-haven assets due to signs of escalating tensions between Russia and the United States over Ukraine.

Three-month copper on the London Metal Exchange (LME) CMCU3 fell 0.3% to $9,042 per metric ton in official open-outcry trading. Spot gold prices XAU= rose by about 1%.

Russian President VladimirPutin on Tuesday lowered the threshold for a nuclear strike in response to a broader range of conventional attacks just days after the White House reportedly allowed Ukraine to fire American missiles deep into Russia.

Ukraine used U.S. ATACMS missiles to strike Russian territory for the first time on Tuesday, Moscow said .

Meanwhile, LME aluminium prices CMAL3 were stable at $2,607 in official activityas the market digested China's plan to remove a tax refund on exports of some aluminium products.

China's Friday announcement that it would cancel a 13% export tax refund for aluminium semi-manufactured products from Dec. 1 inflated concerns that global supplies would tighten up and leave more of the product inside the country.

"In the near term, the cancellation of rebates will make Chinese aluminium (products) more expensive on the international market and could lead to a reduction in export volumes," said Ewa Manthey, a commodities analyst at ING.

LME aluminium will struggle to hold on to the price rally, which saw it hitting $2,730 on Friday, until some physical demand picks up, said a trader.

Lead CMPB3 lost 0.4% to $1,983due to the second day of a significant inflow of the metal to the LME-registered warehouses in Singapore.

The LME data showed on Tuesday that 42,025 tons of lead were delivered on Monday, raising the total stocks to 276,250 tons, their highest since March 2013. MPBSTX-TOTAL

Zinc CMZN3 fell 0.1% to $2,947.5, tin CMSN3 eased 0.4% to $28,900 and nickel CMNI3 rose 1.2% to $15,915.

Reporting by Polina Devitt in London; additional reporting by Ashitha Shivaprasad in Bengaluru; Editing by Varun H K and Louise Heavens

 
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