(Adds analyst comment, updates prices) BEIJING, March 28 (Reuters) - London copper gave up early gains to trade down slightly on Wednesday, tracking a decline in equities on a firmer U.S. dollar and as global trade tensions persisted. The dollar index, which gained about 0.3 percent overnight making metals more expensive for holders of other currencies and weighing on prices, was trading flat at 0500 GMT. However, markets are less volatile now and fluctuations in the base metals were capped, as reports of behind-the-scenes talks between Washington and Beijing spurred some optimism, traders said. "Concerns easing around trade friction are likely to see industrial commodities find support, but volatility is expected to stay high," ANZ wrote in a note.
* LME COPPER: Three-month copper on the London Metal Exchange (LME) was down 0.3 percent at $6,627 a tonne by 0532 GMT, having risen as much as 0.4 percent earlier in the session.
* SHFE COPPER: The most-traded May copper contract on the Shanghai Futures Exchange was flat at 49,470 yuan ($7,881.03) a tonne, giving up slight gains from early trade.
* OTHER METALS: All other base metals were trading down with the exception of Shanghai lead, which gained 0.7 percent to 18.660 yuan a tonne.
* COPPER: Vedanta Resources Plc said on Tuesday its India unit Vedanta Ltd's copper smelting operations at Thootukudi, in the southern state of Tamil Nadu, will be closed for about 15 days as part of a maintenance shutdown.
* ALUMINIUM: China's northern province of Shanxi on Tuesday offered some of the country's biggest aluminium companies preferential access to bauxite resources if they transfer smelting capacity to the region.
* ALUMINA: The Alunorte refinery in northern Brazil, owned half of its alumina capacity in the next two weeks to preserve equipment, two people familiar with the matter said on Tuesday.
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* Asian shares fell on Wednesday after Wall Street was knocked hard by concerns about tighter controls on the tech industry, denting a brief global equities recovery driven by hopes that the risk of a U.S.-China trade war was easing.
BASE METALS PRICES 0500 GMT Three month LME copper 6639 Most active ShFE copper 49470 Three month LME aluminium 2038 Most active ShFE aluminium 13795 Three month LME zinc 3272.5 Most active ShFE zinc 24900 Three month LME lead 2392.5 Most active ShFE lead 18655 Three month LME nickel 12965 Most active ShFE nickel 97060 Three month LME tin 20790 Most active ShFE tin 141080 LME/SHFE COPPER LMESHFCUc3 906.81 LME/SHFE ALUMINIUM LMESHFALc3 -1065.31 LME/SHFE ZINC LMESHFZNc3 510.71 LME/SHFE LEAD LMESHFPBc3 299.2 LME/SHFE NICKEL LMESHFNIc3 387.69
($1 = 6.2771 Chinese yuan)
(Reporting by Tom Daly, Editing by Sherry Jacob-Phillips)