In 2007, it was the fourth largest supplier of petroleum to the United States, after Canada, Mexico and Saudi Arabia. The government-owned PDVSA oil company also owns CITGO Petroleum, which has several refineries in the United States and is the country's third-largest supplier of gasoline.

Chavez, who often rails against President Bush and U.S. policies, has repeatedly threatened to cut off oil shipments to the United States in response to what he views as a possible U.S. attack against his government.

But few believe he can carry out his threat, given that he needs U.S. refineries to process his heavy crude. Chavez recently has been looking to expand his sales to places like China.

Chavez says US can 'shove' terror list

President Hugo Chavez dared the U.S. on Friday to put Venezuela on a list of countries accused of supporting terrorism, calling it one more attempt by Washington to undermine him for political reasons.

Chavez said the "threat to include us on the terrorist list" is Washington's response to his government's successes in the region.