VIENNA/LONDON: The Organization of Petroleum Exporting Countries (OPEC) revised upwards Monday its 2011 world oil demand growth estimate given the pace of global economic recovery, as well as the cold winter weather in the northern hemisphere. "Given the latest upward revision in world GDP (gross domestic product), world oil demand growth is forecast at 1.23 million barrels per day (bpd) averaging 87.3 million bpd in 2011, 50,000 bpd higher than last month's estimate," OPEC said in its latest monthly bulletin. "The magnitude and the speed of the world economic recovery will have a remarkable impact on world oil demand this year," it said, adding: "Weather in the northern hemisphere is gaining momentum and has slightly affected the heating and fuel oil demand." In terms of sector, the petrochemical and transport industries would be the main driver of growth in world oil demand, the cartel stated. And for the second year in a row, demand in industrialized countries - grouped together under the umbrella of the Organization for Economic Cooperation and Development or OECD - had "not only stopped its decline but incurred extra oil usage." Nevertheless, public debt in a number of European economies and continued application of rigorous state tax policies on oil "are some of the factors which could impose future declines in European oil consumption during 2011." In the Pacific region, oil demand in Japan and South Korea would be the engine behind the region's growth this year. It is the fourth month in a row that OPEC - whose 12 member countries pump out 40 percent of the world's crude - has upgraded its 2011 oil demand forecast. Oil prices have risen in recent weeks, with Brent crude passing the $99 mark for the first time in two years in London trading last week. OPEC Secretary-General Abdalla Salem El-Badri blamed the latest surge on speculation. "There were a few technical problems, such as the oil pipeline leak in Alaska. But speculators have seized the opportunity and prices have shot up," El-Badri said in an interview with the Austrian financial daily Wirtschaftsblatt. "We'll have to wait and see. Prices have only been this high for the past two or three weeks." World oil prices drifted lower Monday in thin trade after jumping close to $100 per barrel last week. Brent North Sea crude for delivery in March slipped 73 cents to $97.65 in late afternoon London trade. The February contract spiked to $99.20 Friday ahead of its expiry. New York's main contract, light sweet crude for February delivery dropped 56 cents to $90.98 a barrel. OPEC had no interest in prices that were "either too high or too low," the OPEC chief added. "Oil prices must be high enough to allow for investment. On the other hand, we don't want excessively high oil prices to put the brakes on global economic growth," El-Badri said. He rejected suggestions that OPEC should raise its production to help bring down prices. "No one would buy the oil," he said. "I can assure you: if customers approach our member states and ask for more oil, they will get it. But we can't simply raise the production quotas without a a buyer. "We have to see how the market develops," El-Badri added. "We're monitoring the markets and OPEC will intervene to stabilize the market if the market is unbalanced. But OPEC will not intervene against speculators," he said. OPEC oil ministers signaled Monday the group would not boost output even as prices approached $100 per barrel, despite warnings from the West's energy watchdog, which described prices as “alarming.” The United Arab Emirates' oil minister said he was not concerned by rising prices, echoing comments by other OPEC producers Iran and Venezuela this week. Algeria's oil minister said the oil market was balanced.