New York's main contract, light sweet crude for delivery in November rose 31 cents to $92.24 a barrel and Brent North Sea crude for November delivery gained 29 cents to $110.10.
"You could look at the heightened sanctions against Iran. I would say that's probably the excuse that the market needed to suspend the slide over the last few days," Nick Trevethan, senior commodities strategist for ANZ Research in Singapore, told AFP.
Britain, France and Germany on Monday urged their European Union partners "to further step up the pressure" on Iran by agreeing new sanctions to undermine its nuclear drive, in a joint letter seen by AFP.
The sanctions - set to be formally adopted on October 15 - called for punitive action in the energy, finance, trade and transportation sectors.
Also Monday the US government said the National Iranian Oil Company (NIOC) "is an agent or affiliate of Iran's Islamic Revolutionary Guard Corps (IRGC)".
It said the IRGC, long a target of US sanctions, "has a history of attempting to circumvent sanctions by maintaining a complex network of front companies".
A statement accused the IRGC of "coordinating a campaign to sell Iranian oil in an effort to evade international sanctions".
"NIOC now is also... an agent or affiliate of the IRGC whose property or interests in property are blocked," it added.
"Foreign financial institutions determined to knowingly facilitate significant transactions or provide significant financial services for NIOC will be subject to... sanctions."
The West claims Tehran's nuclear programme is being used to secretly make a bomb but the Islamic republic denies this, saying it is purely for civilian purposes.
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