New York's main contract, light sweet crude for February delivery, eased two cents to $91.52 a barrel and Brent North Sea crude for March delivery was five cents higher at $98.43.

Optimism over the global economic recovery and interest from bullish investors have been the twin drivers behind the surge in crude prices over the past week, analysts said.

"The crude futures are quite close to $100 and speculative traders have generally gone bullish on the market," said Victor Shum, a Singapore-based analyst with energy consultancy Purvin and Gertz.

"There are many investors betting on accelerating global economic recovery, and so we have got these high prices," he told AFP.

The rise in global oil prices has been attributed to a harsh winter hitting Europe and parts of North America, as well as growth in China and other developing nations.

Crude prices first touched $100 a barrel in January 2008 and major oil producer Iran said Sunday it was possible that this would happen again, but ruled out an emergency meeting by OPEC to discuss the matter.

"The price of 100 dollars is not unrealistic in this situation," Iran's Oil Minister Masoud Mirkazemi, who currently heads the OPEC cartel, told reporters on Sunday.

"Even if the oil price crosses 100 dollars a barrel there is no need for an emergency OPEC meeting. Some OPEC members believe there is no need for an emergency meeting even if oil reaches 110 or 120 dollars a barrel."

Iran is OPEC's second largest crude exporter, and holds the world's second largest gas reserves.

The Organisation of the Petroleum Exporting Countries (OPEC), which pumps 40 percent of the world's crude, has said that speculation was also fuelling the price rise.