(Reuters) - Gold edged down towards $1,700 an ounce on Friday, after a fall through an important support level triggered some stop-loss selling as investors anxiously await a key U.S. labor market report.

Gold fell as low as $1,705.79, heading for a fourth straight week of losses ahead of the U.S. nonfarm payrolls data, which is expected to show a pickup in jobs growth, though the unemployment rate may still tick up from a near four-year low in September.

The numbers will follow data on Thursday showing increasing private employment, a drop in jobless claims, a sharp improvement in consumer confidence and mixed signals from the manufacturing sector.

"If the nonfarm payrolls data is very good, it will be bearish for gold, as it will cut expectations for any additional quantitative easing, and it will be fairly positive for the dollar as well," said Nick Trevethan, a senior commodity strategist at ANZ in Singapore.

Chart analysis suggested that gold could test this year's low of $1,527 hit in mid-May during the next three months, but the price needed to pierce through strong support above $1,600, he added.

Short-term technical analysis also painted a gloomy picture. Spot gold could fall to the October 24 low of $1,698.39 an ounce as a rebound from this level is complete, Reuters market analyst Wang Tao said.

Spot gold fell 0.4 percent to $1,708.11 an ounce by 0211 am EDT, on course for a minor drop from a week earlier.

U.S. gold also inched down 0.4 percent, to $1,708.70.

The break below a key support level at $1,710-$1,712 triggered some stop-loss selling in gold, which moved very little in the first hours of trading.

"Length in gold is still very high, and much of it is speculation-driven," said a Hong Kong-based trader.

"We've seen plenty of re-loading by speculators in the past few days and these positions are under pressure before the payrolls data, after the decent ADP report."

The dollar was poised to rise for a second day against a basket of currencies .DXY, putting pressure on commodities priced in the greenback as they become more expensive for buyers holding other currencies.

In industry news, the world's top gold producer, Barrick Gold Corp (ABX.TO), reported a sharp drop in third-quarter profit, nudged back the production date for its massive Pascua-Lama gold and silver mine and increased its estimate on costs.

Newmont Mining Corp (NEM.N), the world's second-largest gold producer, reported a drop of 26 percent in quarterly profit as production at its giant Indonesian copper and gold mine plummeted and costs rose.

Platinum and palladium were both headed for their first weekly gains after three weeks of straight falls, although spot platinum lost half a percent to $1,556 and spot palladium fell 0.7 percent to $606.47.

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