METALS-Copper slips on fears October rally is overstretched

* Metals industry players gathering in London for LME Week

* GRAPHIC-2017 asset returns: http://tmsnrt.rs/2jvdmXl

* LME/ShFE arb: http://bit.ly/2wZSAEz (Updates with official prices)

LONDON, Oct 31 (Reuters) - Copper prices fell on Tuesday as their rebound from Friday's 2 percent drop was arrested by concerns that the market had become overextended during this month's push to three-year highs above $7,000 a tonne.

The red metal used in construction has still risen more than 5 percent this month, benefiting with other commodities from hopes that rising demand from China and the United States would boost prices. However, it is struggling to maintain early gains.

"Demand indicators look relatively poor for copper, and I don't see the supply side as being particularly tight," Oxford Economics analyst Daniel Smith said.

"I think it has just been caught up in this macro story about China improving, and investors coming into commodities quite generally," he said. "I see that as overdone in copper at the moment."

* COPPER PRICES: Three-month copper on the London Metal Exchange was untraded in official rings. It was last bid at $6,830 tonne, down 0.5 percent, erasing most of the previous session's gains and heading towards Friday's two-week low.

* LME WEEK: Volumes are expected to be muted as traders, producers and end-users gather in London for an industry-wide conference this week.

* COPPER TECHNICALS: LME copper may retest support at $6,787 a tonne after its bounce from this level failed to extend above $6,888, Reuters technical analyst Wang Tao said.

* CODELCO: The world's biggest copper miner, Codelco , has raised its 2018 physical copper premium to European buyers to $88 a tonne from the $80 to $85 a tonne range this year, copper industry sources said.

* GLENCORE CUTS: Glencore cut its output forecast for core commodities including zinc, but raised its marketing division's full-year earnings before interest and tax (EBIT) to $2.6 billion to $2.8 billion, reflecting higher raw materials prices.

* FINANCIAL MARKETS: European shares were at a 5-1/2-month high, while the dollar sank to its lowest in nearly two weeks versus the yen on more political unease in the United States.

* ZINC, LEAD PRICES: LME zinc and lead were also untraded in official rings. Zinc was last bid up 1.2 percent at $3,248 a tonne, while lead was up 0.8 percent at $2,430 a tonne.

* ZINC SPREADS: The premium of cash LME zinc over the three-month contract <CMZN0-3> rose to $63 a tonne from $57.50 at the end of last week, climbing back towards the peak of $91 it hit on Oct. 12.

* OTHER METALS: The other metals were also untraded in official midday rings. LME tin was last bid down 0.7 percent at $19,250 a tonne, a new 11-week low. Nickel was last bid 1.6 percent higher at $11,870 a tonne, and aluminium 0.3 percent lower at $2,156 a tonne.

(Additional reporting by James Regan in Sydney; Editing by Dale Hudson and David Evans)