The International Energy Agency, which controls emergency oil stocks held in developed economies, is on "high alert" for potential supply disruption due to political turmoil in the Middle East and North Africa, said the group's head of oil markets Monday.

Around 50,000 barrels a day of oil output from
Libya has been shut down due to the unrest there, said David Fyfe, head of the IEA's Oil Industry and Markets Division at the Energy Institute conference in London .

The IEA controls around 1.6 billion barrels of publicly held oil stocks, but would only use them in the case of a serious supply disruption, not to manage high oil prices, he said.