"We think it's important to do what has to be done in order to prevent Iran from acquiring a nuclear weapon," starting with "engaging directly" with Tehran, spokesman Robert Gibbs told reporters.
Gibbs declined to comment specifically on a New York Times report that a top US official discussed with Israel the possibility of imposing sanctions aimed at starving the Islamic republic of gasoline imports.
Obama will "evaluate" the status of diplomatic overtures to Iran in September and decide on the way forward in the dispute, but "I do not want to get into discussions amongst allies," said Gibbs.
The New York Times reported earlier Monday that the Obama administration was considering sanctions targeting Iran's imports of gasoline and other refined petroleum products.
Obama's national security adviser, Jim Jones, mentioned that possibility to officials in Israel during a visit there last week, the daily said, citing Israeli and European officials.
Because of a lack of domestic refining capacity, oil-rich Iran is dependent on gasoline imports to meet about 40 percent of domestic consumption.
Iran gets most of its gasoline 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.
