Oil prices rose Friday, lifted by upbeat Chinese manufacturing data and a weaker dollar.
New York's main contract, West Texas Intermediate (WTI) for January delivery, rose 84 cents from Thursday to settle at $86.73 a barrel.
Brent North Sea crude for January leaped $1.24 to close at $109.15 a barrel in London trade.
"January Brent crude oil expires today, with late book squaring perhaps contributing something to the strength of the broader market," said Tim Evans of Citi Futures.
More generally supporting crude oil prices was a better-than-anticipated report on manufacturing activity in China that boosted market expectations about demand in the world's biggest energy-consuming country.
"We're seeing reports that manufacturing is expanding at a faster pace than expected and improvement in the Chinese economy translates into more oil demand in the country," said Andy Lipow of Lipow Oil Associates.
British bank HSBC's closely watched purchasing managers index on China's manufacturing activity rose to 50.9 in December, 0.1 point above market expectations. A number above 50 indicates expansion in the sector.
It was the second straight month of growth after a year of contraction, providing a further sign the giant economy is rebounding from a slowdown.
Meanwhile, market concerns about the continued political stalemate in the United States over averting automatic sharp tax increases and spending cuts in January kept up pressure on the dollar.
A weaker US currency tends to encourage demand for dollar-priced commodities.
Economists say allowing the US economy to go over the fiscal cliff will push it into recession.