Adds analyst comment and LONDON dateline, updates prices

By Eric Onstad

LONDON, Oct 15 (Reuters) -Copper prices sank to a three-week low on Tuesday, pressured by confusion about the scale of stimulus measures in top metals consumer China and geopolitical uncertainty.

Three-month copper on the London Metal Exchange (LME) CMCU3 was 1.1% lower at $9,555 per metric ton by 1000 GMT, having touched the lowest since Sept. 24.

Copper and other base metals rallied last month after China announced what seemed to be a massive plan to revive its ailing economy, but since then officials have failed to provide many specifics.

China pledged on Saturday to "significantly increase" debt, but did not give details on the size or the timing of the package.

LME copper rallied 14% from Sept. 4 to the end of the month when it touched a four-month peak, but has since eased 6%.

"People are taking money off the table until they get a bit more clarity on China's growth policies. Most investors I'm speaking to are very confused on that front," said Tom Price, head of commodities strategy at Panmure Liberum.

"U.S. rate policy is now a lot clearer than it has been for months, but everything else is filled with uncertainty," he said, referring to the upcoming U.S. election and ongoing conflicts in the Middle East and Ukraine.

"We're also heading into winter, which generally features destocking, reduced trade flows and reduced deployment of metal," said Price, who expects LME copper to average $9,000 in the fourth quarter.

The most-traded November copper contract on the Shanghai Futures Exchange SCFcv1 fell 1.3% to 76,520 yuan ($10,747.34) a ton.

Adding to investor disquiet was recent data out of China that has missed expectations, including September trade and new lending figures, while another report showed producer price deflation deepened.

Copper got some support from news that Freeport Indonesia has halted copper cathode production activities at its Manyar smelter after a fire.

Among other metals, LME aluminium CMAL3 eased 1.8% to $2,548.50 a ton, nickel CMNI3 lost 1.8% to $17,345, zinc CMZN3 slid 2.5% to $3,007, lead CMPB3 fell 1% to $2,043.50 and tin CMSN3 dropped 1.5% to $31,955.

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Reporting by Eric Onstad
Additionial reporting by Ashitha Shivaprasad in Bengaluru; Editing by Kirsten Donovan

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