World oil prices dropped on Monday as traders worried over the Greek debt crisis, weak global economic outlook and a looming "fiscal cliff" in the United States -- which is the world's biggest oil consumer.
Traders said the market also pushed lower after the International Energy Agency estimated that the US would experience a major rebound in its oil production over the next 10 years.
In late afternoon London deals, Brent North Sea crude for delivery in December fell 31 cents to $109.09 a barrel.
New York's main contract, light sweet crude for December or West Texas Intermediate (WTI), shed 39 cents to $85.68 a barrel.
"Crude oil prices started the week on a consolidation mode, following further uncertainty from the eurozone and especially after last week's heavy sell-off," said Sucden analyst Myrto Sokou.
She added: "We expect further consolidation and thin trading conditions with low volatility until the dust in the eurozone settles."
Greece's debt crisis tops the agenda on Monday when eurozone finance ministers discuss whether Athens has met conditions set by its international creditors to provide bailout funds so it can stay afloat and avert a disastrous default.
Greece's budget paves the way for the European Union, International Monetary Fund and the European Central Bank to unlock a 31.5 billion euro ($40 billion) instalment of bailout funds for Athens.
"Not much on the macro agenda today and (there are) primarily bearish winds blowing in the form of the theoretical Greek default, warnings of slowing German growth and US fiscal cliff worries," added SEB analyst Filip Peterson.
"Even though the (oil) market rarely reacts much to the long term IEA outlook, it definitely weighs that the organisation is getting increasingly optimistic with regards to US tight oil production."
Oil prices were also hit by news that Japan's economy shrank in the July-September quarter, but losses were capped by evidence of strong energy demand in Asian powerhouse China.
Crude futures had advanced on Friday after an extremely volatile week, amid more encouraging news on China's economic soft landing and a jump in US consumer sentiment.
"The robust Chinese import figures should lend support to prices," Commerzbank analyst Eugen Weinberg said on Monday.
"China imported 23.68 million tons of crude oil in October, which is 14 percent up on the previous year's figure.
"This corresponds to an import volume of 5.58 million barrels per day, or the fourth-highest monthly figure since records began."
Separately on Monday, the IEA forecast that the global thirst for oil would grow in the next two decades on keen demand from emerging nations, while the United States would briefly become the world's top producer.
Oil demand was set to increase by 14 percent between now and 2035 to reach 99.7 million barrels a day, the energy watchdog said in its annual assessment of the energy market.
This was 700,000 bpd more than the IEA forecast a year ago and signals that world is still figuring out how to put the global energy system on a more sustainable path, the IEA said.
In its new scenario, the IEA forecast that the US will become the world's top oil producer by 2020, overtaking Saudi Arabia until the mid 2020's.