MELBOURNE, March 19 (Reuters) - London metal prices slipped on Monday on simmering unease that tensions between the world's top two economies could dent demand, while markets turned to this week's Federal Reserve meeting in expectation it could push up the dollar. Further losses could be seen in base metals near term before spreads start to tighten towards the month- and quarter-end, bolstering prices, Kingdom Futures said in a report. "It might well be that we see prices drop as the more speculative longs exit positions and indeed any further sudden falls in global equity markets could trigger a sharp selloff in metals," it said. "That said, as prices fall and sellers get shorter (while) LME stocks ... continue to fall or be cancelled this could well lead to explosive tightness of spreads as we approach the end of Q2 and indeed into Q3." FUNDAMENTALS * COPPER: London Metal Exchange copper had slipped 0.9 percent to $6,828 a tonne by 0203 GMT, extending losses from Friday when prices fell half-a-percent. Prices earlier dropped to $6,811, which was the weakest since March 9 when copper touched $6,777, a break of which would open the way to mid-February lows. Support is seen at the 200-day moving average of $6,657. * SHFE: Shanghai Futures Exchange copper fell 1.2 percent to 51,310 yuan ($8,100) a tonne, the steepest decline among Shanghai metals. * LME COPPER STOCKS: LME copper stocks peaked around 338,000 tonnes in mid-Febraury but have since tailed back to 321,000 tonnes. * SHFE ALUMINIUM: In China, metals inventories have built despite pollution controls that curbed factory output. Shanghai aluminium stocks surged by 87,303 tonnes to a record-high of 934,216 tonnes, data on Friday showed. <AL-STX-SGH > * RISK APPETITE: Worries about the potential for a U.S.-China trade war and frustration over U.S. President Donald Trump's steel and aluminum tariffs threatened to dominate a gathering of finance leaders amid strengthening growth. * CHINA DEMAND: China's new home price growth slowed in February from the previous month as a raft of government curbs aimed at tempering speculative demand softened prices in the biggest cities, although strength seen in smaller centres remained intact. * DOLLAR: The dollar started the week little changed on Monday as traders set sights on new Federal Reserve Chair Jerome Powell's first monetary policy meeting later in the week and as the increased threat of trade protectionism kept markets on edge. * POLLUTION: China will set more stringent targets for improving the nation's air quality under a new three-year plan, as Beijing prepares to beef up a nationwide crackdown on polluters in its years-long campaign to clear its notoriously toxic skies. * INVESTORS: Hedge funds and money managers trimmed their net long positions in COMEX copper contracts in the week to March 13, regulatory data showed on Friday.