The US House of Representatives overwhelmingly approved sanctions legislation aimed at forcing Iran to freeze its nuclear program by depriving the Islamic republic of gasoline.
The measure would empower US President Barack Obama to effectively block firms that supply Iran with refined petroleum products, or the ability to import or produce them at home, from doing business in the United States.
"The prospect of a nuclear-armed Iran is the most serious and urgent strategic challenge faced by the United States, and we must use all of the diplomatic means at our disposal including tougher sanctions to prevent that from becoming a reality," said Democratic Representative Howard Berman.
The House passed the bill, which has yet to clear the Senate, by a 412-12 margin with four voting "present."
A top US senator said recently that body will not act on Iran sanctions in 2009.
Because of a lack of domestic refining capacity, oil-rich Iran is dependent on gasoline imports to meet about 40 per cent of domestic consumption.
Iran gets most of those imports from the Swiss firm Vitol, the Swiss/Dutch firm Trafigura, France's Total, the Swiss firm Glencore and British Petroleum, as well as the Indian firm Reliance.