House Speaker Dennis Hastert, R-Ill., and Senate Majority Leader Bill Frist, R-Tenn., urged Bush in a letter Monday to order a federal investigation into any gasoline price gouging or market speculation.

"There is no silver bullet," Frist said Tuesday on ABC's "Good Morning America," but "we need to make sure that any efforts at price-gouging be addressed and addressed aggressively." Meanwhile, Frist said, consumers should take steps to conserve gasoline ¡ª drive at slower speeds, tune up car engines for maximum efficiency and carpool.

McClellan said Bush had already ordered investigations into market pricing.

"We share a commitment with congressional leaders to make sure that we're acting to ensure that there is no price gouging," McClellan said.

Senate Democratic leader Harry Reid of Nevada dispatched his own letter, calling for a multi-pronged approach to restrain gas prices. Among the steps were swift enactment of anti-price gouging legislation, an appeal to oil companies to refrain from further price increases, use of more alternative fuels and increased attention to existing fuel-saving laws and regulations.

Bush also planned to announce that his attorney general and Federal Trade Commission will send a letter to all 50 state attorneys general, who have primary authority over price gouging, to remind them to stay on top of the issue and offer federal help to do so. And he planned to call on energy companies to reinvest their profits into expanding refining capacity, developing new technologies and researching alternative energy sources, McClellan said.

"I think you'll hear the president say very clearly that he will not tolerate price gouging," McClellan said.

Bush has said consistently that gas prices are high because global demand is rising faster than global supply and that the problem cannot be solved overnight. McClellan said Bush planned to talk about how experts predict the price will increase this summer and how the switch to a summer fuel mix is contributing to the problem.

Bush's actions are part of a four-part plan to address gas prices in the short- and long-term, McClellan said. The steps are:

Making sure consumers and taxpayers are treated fairly.

Promoting greater fuel efficiency.

Boosting gasoline supply at home.

Aggressive long-term investment in alternative fuels.