By Sam Forgione

NEW YORK (Reuters) – Stock indexes worldwide slipped on Monday after weaker-than-expected Chinese trade data and on uncertainty about Greece’s position in the eurozone, while oil prices rose after an optimistic demand forecast from OPEC.

Wall Street stocks dipped, while European shares were last down 0.5 percent after data on Sunday showed China’s exports fell 3.3 percent from a year ago while imports tumbled 19.9 percent, raising concerns about the world’s second-largest economy.

Also on Sunday, Greek Prime Minister Alexis Tsipras ruled out extending the country’s bailout and said he would reverse some of the reforms imposed by its lenders, escalating tensions between Greece and its European partners and raising fears of a Greek exit from the euro zone.

Tensions rose further on Monday after European Commission President Jean-Claude Juncker said Greeks should not expect the euro zone to accept the latest terms proposed by Greece. Greek banking shares tumbled.

“We are seeing heightened nervousness over the Greek elections and the policies that could make or break its EU membership,” said Andre Bakhos, managing director at Janlyn Capital LLC in Bernardsville, New Jersey.

“In addition, the Chinese economic data disappointed and added to the economic global weakness we have been seeing.”

Escalating violence in Eastern Ukraine also weighed on shares. German Chancellor Angela Merkel will meet U.S. President Barack Obama later in the day to discuss the conflict in Ukraine, where nine troops and seven civilians have been killed in the past 24 hours alone.

Oil prices rose for a third straight session as OPEC forecast greater demand for crude this year than previously thought and projected less supply from countries outside the group. Benchmark Brent oil futures <LCOc1> revisited Friday’s one-week peak of $ 59.06.

The Japanese yen firmed against the U.S. dollar after two straight days of losses, largely on the concerns over Greece’s status and the conflict in Ukraine.

The Dow Jones industrial average <.DJI> was last down 0.35 percent, at 17,761.06. The S&P 500 <.SPX> slipped 0.19 percent, to 2,051.6. The Nasdaq Composite <.IXIC> was down 0.28 percent, at 4,731.33.

In Europe, the FTSEurofirst 300 index <.FTEU3> of top regional shares 0.90 percent, to 1,477.41. MSCI’s all-country world stock index <.MIWD00000PUS> fell 0.28 percent, to 419.33.

Safe-haven U.S. Treasury yields edged lower. Yields on benchmark 10-year U.S. Treasury notes, which move inversely to prices, were last at 1.92 percent, from 1.94 percent late Friday.

Brent crude <LCOc1> was last up 81 cents at $ 58.61 a barrel. U.S. crude <CLc1> was last up $ 1.70 at $ 53.39 per barrel.

The dollar was last down 0.44 percent against the yen at 118.61 yen <JPY=EBS>. The dollar index <.DXY>, which tracks the greenback versus a basket of six currencies, was down 0.27 percent, at 94.445.

The weakness in European equities helped gold edge higher and recover from a three-week low posted Friday after strong U.S. payrolls data boosted the dollar. Spot gold prices <XAU=> rose $ 7.33 or 0.59 percent, to $ 1,240.55 an ounce.

(Reporting by Sam Forgione; Additional reporting by John Geddie in London, Blaise Robinson in Paris, and Chuck Mikolajczak and Gertude Chavez-Dreyfuss in New York)