SINGAPORE, Nov 19 (Reuters) - London copper was almost unchanged on Monday as tensions between Washington and Beijing at a regional summit renewed concerns over a prolonged trade war, weighing on prices although the market was supported by tightening supplies. U.S.-China trade tensions were clearly on display at an Asia Pacific economic summit in Papua New Guinea over the weekend, where leaders failed to agree on a communique for the first time ever. COPPER: Three-month copper on the London Metal Exchange was almost flat at $6,203 a tonne, as of 0408 GMT, while the most-traded copper contract on the Shanghai Futures Exchange climbed 0.2 percent to 49,680 yuan ($7,156.34) a tonne. COPPER SUPPLY: Headline copper inventories in LME-registered warehouses MCUSTX-TOTAL fell by 5,425 tonnes to 161,025 tonnes, nearing last month's 10-year low of 136,675 tonnes. PREMIUM: The premium of cash copper over the three-month contract MCU0-3 drifted to $18.50 from a near four-year high of $47 last month. VEDANTA: India's Vedanta Ltd has been selling copper concentrate on the spot market from stockpiles at its Sterlite smelter, disposing of around 70,000 tonnes of copper concentrate unused since the plant closed earlier this year amid pollution concerns. DOLLAR: The dollar was modestly lower against its key rivals on Monday after Federal Reserve officials expressed caution over the global growth outlook, prompting traders to reassess the pace of future U.S. interest rate increases. * LUNDIN: Canadian miner Lundin said it was cutting 106 jobs at its Candelaria copper mine in Chile to "improve competitiveness and productivity", amid reports that workers had begun a 48-hour strike. * BARRICK: Barrick Gold Corp , soon to become the world's largest bullion miner, is interested in adding more copper assets as long as the red metal is accompanied by bullion, executives said on Friday. * NICKEL: London nickel dropped 1.1 percent to $11,240 a tonne, after Chinese steel prices dropped to the lowest in nearly four months on Monday, pressured by expectations that steel output in the world's top producer will remain strong as cities impose more flexible production curbs this winter. * OUTPUT: Nickel output in the Philippines, a major supplier of the metal, is expected to increase after the country's environment ministry said nine suspended mines will be allowed to resume operations if they rectify previous violations of environmental regulations.