(Adds Shanghai closing prices, updates London prices) BEIJING, March 20 (Reuters) - London Metal Exchange (LME) copper prices lost ground for a fourth session on Tuesday, tracking a fall in equities as investors trimmed positions ahead of a U.S. Federal Reserve meeting starting later in the day. The Fed is widely expected to raise interest rates for the United States this week for the sixth time since December 2015 at the two-day policy meeting, the first under new Chairman Jerome Powell. "The risk-off tone in global markets, alongside relatively weak economic data, is likely to keep commodity prices under pressure," ANZ wrote in a note. Higher U.S. rates may support a rising dollar, which would limit demand for dollar-denominated commodities such as copper from buyers paying with other currencies. Copper had fallen on Monday after top metals consumer China's new home price growth slowed in February from the previous month.
* Three-month copper on the LME was down 0.1 percent to $6,847 a tonne by 0749 GMT, extending a 0.5 percent dip from the previous session, and trading in a narrow range of less than $50. SHFE COPPER: The most-traded May copper contract on the Shanghai Futures Exchange closed down 0.3 percent at 51,440 yuan ($8,128.31) a tonne. It earlier touched 51,120 yuan a tonne, its lowest since March 9.
* USD: The dollar index edged up 0.2 percent to 89.93.
* OTHER METALS: LME zinc and lead slipped 0.5 percent and 0.7 percent, respectively, while nickel, used to make stainless steel, recovered from early losses to close up 0.1 percent in Shanghai and was up 0.5 percent in London.
* ALUMINIUM: Japanese trade minister Hiroshige Seko said on Tuesday that there was a high possibility Japan would be exempted from U.S. tariffs on steel and aluminium on a per-item basis.
* COBALT: Nervous Asian battery makers are turning to early-stage cobalt projects in Australia and Canada to lock in supplies of the critical battery ingredient ahead of expected shortages as demand for electric vehicles revs up.
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* Asian shares were on the defensive on Tuesday after investors took profits in high-flying U.S. technology shares on fears of stiffer regulation, as Facebook came under fire following reports it allowed improper access to user data.
BASE METALS PRICES 0727 GMT Three month LME copper 6850 Most active ShFE copper 51430 Three month LME aluminium 2085.5 Most active ShFE aluminium 13990 Three month LME zinc 3242 Most active ShFE zinc 24765 Three month LME lead 2353 Most active ShFE lead 18320 Three month LME nickel 13560 Most active ShFE nickel 102770 Three month LME tin 20780 Most active ShFE tin 143700
BASE METALS ARBITRAGE
LME/SHFE COPPER LMESHFCUc3 975.36 LME/SHFE ALUMINIUM LMESHFALc3 -1326.3 LME/SHFE ZINC LMESHFZNc3 453.68 LME/SHFE LEAD LMESHFPBc3 227.25 LME/SHFE NICKEL LMESHFNIc3 1092.03
($1 = 6.3285 Chinese yuan)
(Reporting by Tom Daly, Editing by Christian Schmollinger and Sherry Jacob-Phillips)