Brent oil crude futures eased slightly on Monday, as last week's weaker data lingered over a market thinned by public holidays in the United States and Britain.
Oil came under pressure last week as data showed China's factory activity declined in May for the first time in seven months and U.S. manufacturing grew at its slowest pace since October. The United States and China are the world's top two oil consumers.
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Producer cartel the Organisation of the Petroleum Exporting Counties (OPEC), is odds on to leave output policy unchanged, say delegates who attend meetings.
As a risk factor for oil markets, its May 31 gathering in Vienna barely features on traders' radar.
"There is a risk that prices go down due to demand concerns and that OPEC is unlikely to change anything at the meeting this week," Carsten Fritsch, oil analyst at Commerzbank in Frankfurt said.
One reason is that Brent oil prices are very close to top producer Saudi Arabia's favoured $100 a barrel, meaning the producer with the most sway is unlikely to call for a production cut.
"People will slowly move towards $100 a barrel at the end of the week unless something unexpected happens in the financial markets or geo-political landscape," Fritsch at Commerzbank said.
Data last week also showed stockpiles of gasoline in the United States are close to the highest level for this time of year since 1999.
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