Crude oil slipped from 18-month highs around $87 a barrel after six straight sessions of gains as the dollar strengthened broadly, and copper retreated from Tuesday's 20-month high.

The spread between Greek government bond yields versus German Bunds blew out to record levels as skepticism over Greece's ability to fund its debt at current levels refused to fade.

A downward revision to euro zone economic growth to zero from a previous reading of growth of 0.1 percent highlighted the fragility of the recovery in Europe, helping push global stocks down and adding to the gloom caused by Greece's nagging debt problems.

Before 1 p.m., the Dow Jones Industrial Average was down 39.45 points, or 0.36 percent, at 10,930.54. The Standard & Poor's 500 Index was down 3.21 points, or 0.27 percent, at 1,186.23. The Nasdaq Composite Index was down 0.85 points, or 0.03 percent, at 2,435.96 Energy shares fell with the drop in crude oil prices.

Sentiment was further dented by news that Greek banks have asked the government for more financial support, highlighting the problems facing Greece, whose economy is expected to contract by at least 2 percent this year.

The pan-European FTSEurofirst 300 index of top shares fell 0.3 percent to close at 1,098.16 points, after hitting an 18-month closing high for the second straight session on Tuesday.

Banking shares were among the biggest drags on the index.

Greek banks lost 4.2 percent.

The euro dropped against the dollar to its lowest in more than a week, down 0.36 percent at $1.335.

"The GDP data, even though it is backward-looking, shows the euro zone is in a difficult situation. The outlook is negative overall for the euro," said Antje Praefcke, currency strategist at Commerzbank.

Greek concerns resurfaced on reports that Greece wanted to renegotiate a deal reached last month over joint European Union-International Monetary Fund aid. Greece denied the reports.

The US Dollar Index was up 0.23 percent at 81.578, while against the yen, the dollar was down 0.21 percent at 93.55.

US Treasury debt made modest gains ahead of an auction of 10-year notes after a sell-off late last week on improved economic data that pushed yields up enough to attract buyers.

Lingering concern about Greece also revived the appeal of safe-haven US government debt. Longer-dated debt prices earlier in the session were slightly lower.

The benchmark 10-year US Treasury note rose 7/32 in price, pushing the yield down to 3.93 percent.

Gold rose to a five-week high, near record levels in euro terms, on strong physical demand and as investors, worried by the outlook for the euro-zone economy, flocked into hard assets.

Spot gold prices rose $17.05 to $1,150.70 an ounce.

Oil prices fell on Wednesday. US light crude futures for May were 20 cents lower at $86.64 by 1:37 p.m. EDT (1737 GMT), but up from the intraday low of $85.75. On Tuesday, US crude reached an intraday peak of $87.09, its highest since October 2008.

London ICE Brent had bounced and was up 12 cents to $86.27.

US crude oil inventories rose for a 10th straight week, lifting stocks to the highest level since mid-June 2009, the US Energy Information Administration said on Wednesday.

Crude inventories rose by 2 million barrels to 356.2 million barrels in the week to April 2, the highest since supply hit 357.7 million barrels in the week to June 12, 2009, according to EIA data.

The EIA's report had a bigger build than Tuesday's data from the American Petroleum Institute trade group, which reported crude oil stocks rose 1.1 million barrels.

Gasoline stocks fell to 222.4 million barrels, a drop of 2.5 million barrels, the EIA said. The forecast was for a drawdown of 800,000 barrels.

Distillates, including heating oil and diesel, snapped a series of declines, rising 1.1 million barrels to 145.7 million barrels. The forecast was for a drop of 1.2 million barrels.

Jim Ritterbusch, president at Ritterbusch & Associates said the EIA data looked "bearish on most counts with crude stocks building more than expected, distillate stocks posting a counter-seasonal build and gasoline draw falling short of our 3 million barrel expectations."