New York’s main contract, light sweet crude for delivery in April, firmed 31 cents to close out the week at 63.67 dollars a barrel.

In London, the price of Brent North Sea crude for April delivery finished up 11 cents at 64.18 dollars a barrel.

"I think you had some people squaring positions ... a little bit leery about holding shorts in front of the IAEA testimony," AG Edwards analyst Bill O’Grady said, describing trading as "pretty slow."

On Monday in the Austrian capital, the International Atomic Energy Agency (IAEA) meets to ponder whether to recommend UN sanctions against Iran over its disputed nuclear programme.

Then on Wednesday, also in Vienna, the Organization of Petroleum Exporting Countries is to hold its latest meeting to set production levels.

"Concerns over the potential for fresh disruption to supply in Nigeria and a heightened sensitivity to Iran’s nuclear ambitions as Monday’s IAEA meeting looms" supported prices, Barclays Capital analyst Kevin Norrish said.

Iran, the second-biggest producer in OPEC after Saudi Arabia, is accused by Western powers of seeking nuclear weapons under cover of a civilian energy programme.

No agreement was reached Friday among Iran, France, Germany and Britain during lastditch talks in Vienna aimed at allaying the nuclear fears.