New York's main contract, light sweet crude for April delivery, rose four cents to USD 95.46 per barrel.
Brent North Sea crude for delivery in April went up 22 cents to USD 106.
"Sustained protests (in the Middle East) could inject huge amount of uncertainty in the oil market in the medium term," said Chen Xin Yi, a Singapore-based commodities analyst for Barclays Capital.
The unrest in the key oil-producing Middle East and North African region which includes Libya, Bahrain, Yemen and Iran has stoked fears of disruption to global crude supplies, analysts said.
Libya, which has Africa's largest oil reserves and is the continent's fourth largest producer, is a member of the Organisation of the Petroleum Exporting Countries (OPEC), the cartel that produces about 40 per cent of global supplies.
Libyan leader Moamer Kadhafi's pledge to crush anti-regime protesters raised the stakes in an increasing bloody fight for control of the country, a fight that could halt oil shipments.
Speaking on the sidelines of a producer-consumer meeting in the Saudi capital Riyadh on Tuesday, Saudi Oil Minister Ali al-Naimi said OPEC was prepared to meet any shortage of supplies.
"There is absolutely no shortage of supply now... OPEC is ready to meet any shortage in supply when it happens," Naimi said.
"There is concern and fear but there is no shortage," the minister reiterated in a bid to assure consumer countries that crude oil supplies are guaranteed despite sweeping unrest.