LONDON?World oil prices weakened on Monday as traders turned their attention towards this week's crucial output meeting of the OPEC oil cartel.

New York's main contract, light sweet crude for April delivery, fell $0.34 to $80.90 a barrel.

London's Brent North Sea crude for April retreated $0.41 to $78.98 per barrel.

"Macroeconomic data is relatively scarce this week and we expect renewed focus on fundamentals (of supply and demand), also with OPEC's scheduled meeting on Wednesday," said VTB Capital analyst Andrey Kryuchenkov.

"We expect no surprises and no change to the exporting group's output policy, while members are likely to pledge improving compliance."

The Organization of Petroleum Exporting Countries (OPEC) will likely keep its official output quota at 24.84 million barrels a day when it meets in Vienna, according to oil industry experts.

OPEC's member nations together pump around 40 percent of the world's crude oil supplies.

The powerful grouping of 12 Middle Eastern, African and Latin American oil producing countries has the same daily official output level, excluding production by Iraq, since January 2009.

Before the weekend, oil had fallen after news of a surprise decline in consumer confidence in the United States, triggering concerns about demand in the world's biggest economy and top energy consumer.

The University of Michigan's consumer confidence index dropped for the second consecutive month in March, to 72.5 from 73.6 in February, instead of rising to 74.0 as analysts expected.

Meanwhile, the International Energy Agency raised its forecast for global demand in 2010 Friday citing an "astonishing" growth trend of 28 percent in China as advanced economies emerge from recession.

The agency revised its forecast to 86.6 million barrels per day (mbd) from its projection last month of 86.5 mbd?a 1.8 percent increase from 2009 demand levels.