New York's main contract, light sweet crude for delivery in December, rose 21 cents to $87.06 a barrel after reaching $87.49 - the highest point since late 2008.
In London, Brent North Sea crude for December rose 35 cents to $88.46 a barrel.
"It's been just a quiet day after all the craziness last week," said analyst Matt Smith of Summit Energy.
"There's little to dictate movement on the crude market. Just keeping an eye on the equity market and some dollar strength."
Oil prices have been boosted in recent days by the US Federal Reserve's decision to inject an additional $600 billion into the market to help stimulate the world's biggest economy.
On Monday, the US dollar gained ground against key currencies, putting some downward pressure on oil prices.
The stronger greenback makes dollar-priced oil more expensive for investors outside the United States.
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