LONDON, Feb 21 (Reuters) – Copper prices slipped from seven-month highs on Thursday as the dollar firmed and investors cashed in gains from a rally in the previous session fuelled by falling inventories. The dollar found strength in minutes from a U.S Federal Reserve meeting that raised expectations of a possible U.S. interest rate increase this year. Three-month copper on the London Metal Exchange ended 0.4 percent lower at $6,379 a tonne, having hit its highest since July 10 at $6,426.50 in the previous session. On Wednesday LME copper broke through technical resistance at $6,400, which triggered profit-taking alongside a stronger dollar, said Saxo Bank commodities analyst Ole Hansen. “But overall the story driving copper is the worries about supply,” he said. Miner and trader Glencore lowered its 2019 copper output forecast to 1.5 million tonnes from 1.54 million tonnes, citing production cuts at its Mutanda mine in the Democratic Republic of Congo. “(That) supports the idea that supply is tightening in copper and has helped it move ahead despite the headwinds from the uncertainty related to global economic growth,” Hansen said. The metal used in power and construction has registered reduced inventories while supply has been constrained by lack of investment in mines and declining grades. STOCKS: Stocks of copper in LME warehouses stand at 137,700 tonnes, close to 10-year lows of 122,500 tonnes hit in early December last year. DOLLAR: The U.S. currency gained against a basket of major currencies. A stronger greenback makes dollar-denominated commodities more expensive for non-U.S. firms in a relationship used by funds to generate buy and sell signals. TRADE TALKS: The United States and China have started to outline commitments in principle on the stickiest issues in their trade dispute, the most significant progress yet toward ending a seven-month trade war, sources said. Signs of progress in trade talks usually boost metals and equities, but markets had been “brewing on that theme for too long and most of the positive news has been priced in already”, said Saxo Bank’s Hansen. TIGHT ZINC: The premium for cash zinc over the three-month LME contract rose to $26.50 as stocks in LME warehouses fell to their lowest since 2017 at 83,250 tonnes. ALUMINIUM: Global primary aluminium output fell to 5.304 million tonnes in January from revised 5.498 million tonnes in December, data from the International Aluminium Institute showed, with the bulk of this coming from winter production cuts in China.  Aluminium rose 2 percent to $1,905 per tonne.