OPEC's president Sheikh Ahmad Fahd al-Sabah, who is also Kuwait's energy minister, said Monday the cartel will pump an extra 500,000 barrels a day in May to calm supply fears.

Over the weekend, the Group of Seven Industrialized nations - comprising the United States, Japan, Germany, France, Britain, Italy, and Canada - asked OPEC to lower prices by increasing output.

Last month, the Organization of the Petroleum Exporting Countries boosted its production quota by 500,000 barrels a day to 27.5 million barrels.  OPEC's 11 members supply nearly 40 percent of the world's crude oil. 

In Monday's trading, crude oil for May delivery rose 41 cents to $50.90 a barrel on the New York Mercantile Exchange. Prices remain about 30 percent higher than a year ago.

Some information for this report provided by AP, AFP.