The Organization of Petroleum Exporting Countries says it will make another two million barrels of crude oil available to refiners each day.
The decision was expected, and was formally announced Tuesday in Vienna, where top OPEC officials have been discussing oil production and prices.
Some analysts say the gesture is largely symbolic because most OPEC member nations have been producing all the oil they can as demand and prices have hit new highs.
Only Saudi Arabia is thought to have significant unused capacity.
Some experts say high gasoline prices that have sparked protests in some European countries grow out of a shortage of refining capacity, rather than a lack of crude oil.
Some information for this report provided by AFP, AP and Reuters.