BEIJING, March 20 (Reuters) - London Metal Exchange (LME) copper prices fell 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. FUNDAMENTALS * LME COPPER: Three-month copper on the LME was down 0.3 percent to $6,833.50 a tonne by 0412 GMT, extending a 0.5 percent dip from the previous session. * SHFE COPPER: The most-traded May copper contract on the Shanghai Futures Exchange was down for a third straight day, falling by 0.7 percent to 51,240 yuan ($8,100.03) a tonne by the mid-session interval. It earlier touched 51,120 yuan a tonne, its lowest since March 9. * USD: The dollar index edged up 0.2 percent to 89.90. * OTHER METALS: LME zinc and lead were down by around 1 percent each, while nickel, used to make stainless steel, slipped by 1.3 percent in Shanghai, mirroring a dip in the ferrous complex, and was down 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. * MONGOLIA: Switzerland's highest court has upheld the seizure of $1.85 million in Swiss bank accounts, part of a corruption probe linked to a former Mongolian finance minister who helped clear the way for a disputed Rio Tinto mining project, a ruling showed. * 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.