Caution ahead of an audit of Greece's finances drove major world stock markets lower on Wednesday, while prices of commodities like oil and copper fell.

Following its best day in a year and a half, an index of world stocks dropped as investors awaited news on whether Greece will be allowed another round of aid in order to avoid a default.

The focus was also on whether European leaders could agree on an enlarged bailout fund to help other debt-laden nations in the region.

The European Union confirmed negotiators would return to Greece this week to discuss issuing its next tranche of aid.

U.S. stocks turned mostly lower after opening higher.

Commodities rolled over, the dollar is at the highs of the day, but I didn't see any news behind (the market turnaround), said Peter Boockvar, equity strategist at Miller Tabak & Co in New York.

It has been widely expected that the EU, IMF and European Central Bank would eventually approve the release of money Greece needs to avoid default. But after a boost to commodities and equities in the past days, markets acknowledge the risk is that optimism has been premature.

It is certainly interesting that we had that nice rally (in U.S. stocks) yesterday and gave it all back late afternoon, said Frank Lesh, a futures analyst and broker at FuturePath Trading LLC in Chicago.  

It just shows how nervous the markets are and it is tough to commit; we will probably continue like this until there is a little more clarity (in Europe), and who knows when that comes.

After more than 90 minutes of trading in New York, the Dow Jones industrial average was down 5.37 points, or 0.05 percent, at 11,185.32. The Standard & Poor's 500 Index was down 4.12 points, or 0.35 percent, at 1,171.26. The Nasdaq Composite Index was down 9.02 points, or 0.35 percent, at 2,537.81.

U.S. stocks were supported by data showing new orders for long- lasting U.S. manufactured goods slipped in August while a rebound in a gauge of business spending supported views the economy would likely avoid another recession.

An index of world stocks fell 0.5 percent a day after rising more than 3 percent on Tuesday --its largest daily percentage advance since mid-May 2010.

Equity markets have rallied over the past few sessions on expectations European officials will aggressively tackle the debt crisis by boosting the euro zone's 440 billion euro rescue fund, known as the EFSF.

But an increase in the EFSF faces opposition in Germany and there are signs of a split within the currency bloc over the terms of Greece's next bailout.

Benchmark U.S. Treasury yields hovered near 2 percent before a $35 billion sale of five-year notes. The less-pessimistic U.S. data added to hopes for bold steps to combat Europe's debt crisis, keeping a lid on demand for bonds.

The euro trimmed gains against the U.S. dollar shortly after the U.S. new orders and business spending data and was near unchanged for the day. The single currency had previously hit a one-week high versus the greenback.