* Brent at 12-week low; weeklong loss worst in 2 years
* Copper ends near 6-week lows, gold slips below $1,700
* Cocoa down 4 pct, biggest commods loss in US session
* Wheat bucks downtrend, rallying on Ukraine export ban
NEW YORK, Oct 24 (Reuters) - Brent crude fell for a seventh straight session on Wednesday, hitting 12-week lows after a sharp build in U.S. oil stockpiles, while most other commodities slid too as the dollar remained strong against the euro. Copper closed near six-week lows, and gold slipped below $1,700 per ounce for the first time since September. Cocoa futures tumbled 4 percent, falling more than any other commodity in Wednesday's U.S. session, on technical liquidation executed through computer-triggered sale orders. Wheat was one of the few markets that bucked the downtrend, rallying after Ukraine's widely expected ban on exports of the grain due to a weather-damaged harvest. Wheat futures hit one-month highs in Europe and a three-week peak in Chicago trade. The Thomson Reuters-Jefferies CRB index, a bellwether for commodities, fell 0.7 percent to its lowest since Aug. 3. The index has dropped for four straight sessions, with 11 of its 19 components down on Wednesday.
SURGE IN US OIL STOCKPILES Crude oil stocks in the United States jumped by 5.9 million barrels last week, the U.S. Energy Information Administration said, well above the increase of 1.9 million barrels forecast by analysts in a Reuters survey. Gasoline stocks rose more than expected, total distillate stockpiles eased slightly less than the consensus forecast and demand for the products over the previous four weeks came in below the year-ago period. ``The report is mostly bearish, with the large increase in crude oil inventories being the highlight,'' said John Kilduff, partner at Again Capital LLC in New York. London's Brent crude, which determines global oil prices more these days than U.S. crude, settled down 0.4 percent at $107.85 a barrel after striking its lowest level since Aug. 6. The market has closed lower each session since Oct. 16. Brent last fell for seven straight sessions in July 2010.
U.S. crude settled at $85.73 a barrel, down 1 percent.
DOLLAR PULLS METALS DOWN Copper and gold fell under the weight of the rising dollar. The U.S. currency rallied against the euro for a second day, after Germany's Ifo business sentiment index fell in October for a sixth consecutive month to the lowest level since February 2010, stoking worries that Europe's largest economy may be headed for recession. Other euro zone economies also issued weak data. Purchasing managers' data showed the Chinese economy was slowly picking up from its weakest period of growth in three years. But that failed to lift prices of base metals, which depend largely on consumption in China, the world's largest metals buyer. ``I don't think one should expect too much from China in terms of a pick-up given the government is in transition,'' Societe Generale analyst Robin Bhar said. ``The negative news is priced in but, equally, until economies start to move higher, we're not going to challenge the upside.'' Benchmark three-month copper futures in London closed down $14, or 0.2 percent, at $7,817 a tonne. They touched $7,807.75 on Tuesday, the lowest level in six weeks.
NO ``GAMES'' IN WHEAT Wheat prices soared after Ukraine's farm minister confirmed the country would ban exports of the grain from Nov. 15, marking the exit of another major Black Sea exporter from the global grains market. ``We are not playing games here. We do not have any other option,'' Farm Minister Mykola Prysyazhnyuk told Reuters after the country lost a third of its harvest from bad crop weather. One of the world's top 10 global wheat exporters, Ukraine's supply of the grain had become all the more important this year after a drought severely affected U.S. crops. Front-month wheat futures on the Chicago Board of Trade fetched above $8.80 a bushel, up 1.6 percent and at a three-week high. European milling wheat in Paris rose half a percent to 264.75 euros a tonne, having set a one-month high at 267.50 euros.
Prices at 2:53 p.m. EDT (1853 GMT)