At 11:11 am (0311 GMT), New York's main contract, light sweet crude for delivery in February, was up seven cents at 65.80 dollars a barrel from its close of 65.73 dollars in the United States Wednesday, where it had earlier struck 66.93 dollars -- the highest level since September 22.

Iran, the second biggest crude exporter in the Organisation of Petroleum Exporting Countries (OPEC), is facing possible United Nations sanctions over its nuclear programme, triggering concerns over supply from the Middle East producer, dealers said.

In defiance of the UN's International Atomic Energy Agency (IAEA), Iran last week broke the seals on a nuclear facility to resume research on uranium enrichment after a voluntary suspension.

Iran's move has intensified fears that the regime is seeking to make an atomic bomb. The country insists it only wants to make reactor fuel to generate electricity.

Diplomats say Iran is almost certain to be referred to the UN Security Council when the IAEA board of governors meets in Vienna on February 2.

There are also concerns about supplies from Africa's biggest producer, Nigeria, where separatists blamed for a string of attacks on oil installations have called on foreign energy companies to leave.