WASHINGTON – President Bush, facing voter concern over soaring fuel prices, said he will free up oil that is being added to the nation’s emergency reserves and waive rules that are creating bottlenecks in American gasoline markets.

Mr. Bush, in a speech yesterday in Washington to the trade group for ethanol producers, said the country should raise fuel efficiency and develop alternatives to oil. He also ordered the Justice Department to look for possible price manipulation. Democratic lawmakers said Mr. Bush’s proposals would do little to lower prices.

“We’ll leave a little more oil on the market” by halting deliveries to the reserves, Mr. Bush said. “Every little bit helps.” He said the fuel rule waivers would address concerns about local shortages as refiners switch to ethanol as the most common gasoline additive.

Mr. Bush and Republicans in Congress face growing pressure from voters as crude oil soars to a record and gasoline pump prices near the all-time high reached after Hurricane Katrina last year. A CNN poll released yesterday showed 69 % of American adults say higher fuel costs are causing financial hardship.

The Energy Department will suspend deposits to the Strategic Petroleum Reserve through the end of summer, which is the period of peak demand in America, Mr. Bush said.

Because the stockpile is nearly full, the effect of the halt may be minimal. The government has been adding an average of about 25,000 barrels of oil per day to the reserve so far this year. America imports about 10 million barrels a day.

The American oil reserve, located in salt caverns along the Gulf Coast, is meant to be used in case of a sudden supply disruption. Mr. Bush repeatedly has said he would not release reserves into the market just because prices are high. The reserve was full with more 700 million barrels before Katrina shut Gulf of Mexico production and prompted Mr. Bush to tap it.

Crude oil surged to a record $75.35 a barrel on the New York Mercantile Exchange last week amid concern that Iranian oil supplies might be jeopardized by the dispute over Iran’s nuclear program. Oil fell 43 cents to $72.90 a barrel at 2:30 p.m. in reaction to Mr. Bush’s speech.

The investigation by the Federal Trade Commission and the Justice Department was sought by the Republican leaders of the House and Senate. It renews Mr. Bush’s directive to the FTC after Katrina hit to be on the watch for price gouging.

“The first thing to do is to make sure Americans are treated fairly at the gas pump,” Mr. Bush said. “This administration is not going to tolerate manipulation.”

Boone Pickens, the Dallas hedge fund manager and a Bush supporter, said he was disappointed that Mr. Bush is talking about investigations.

“There’s not anything there. There’s not anybody gouging,” Mr. Pickens said in an interview today at the Milken Institute conference in Los Angeles. “You have the Federal Trade Commission looking at gasoline prices every day.”

Attorney General Gonzales and FTC chief Deborah Platt Majoras today sent letters to state attorneys general pledging cooperation on investigations and saying the agencies “have substantially increased our efforts at the federal level to monitor, detect, pursue, and prevent any violations of the law in this industry.”

The FTC will send a final report to Congress by May 19 on whether businesses have manipulated gasoline markets and prices.

Past investigations of price gouging have concluded that “the industry is reasonably competitive and the explanation for price increases lies in other causes,” the president of the American Antitrust Institute, Bert Foer, said. The chance investigators will find anything “strikes me as fairly low,” he said.

The average retail price of gasoline nationwide is $2.914 a gallon, according to the Department of Energy, and prices exceed $3 in Los Angeles, New York, and Washington. Mr. Bush’s 14-vehicle motorcade to today’s event passed an Exxon station next to the Watergate complex that was selling gasoline for $3.29 a gallon.

In his speech, Mr. Bush repeated past statements that high prices are a result of worldwide demand outstripping supply.

The president said the actions America must take are encouraging greater fuel efficiency for cars and trucks, including more use of hybrid vehicles, and expanding domestic production and refining capacity.

He said the steps described today are “short-term” remedies. The real solution, he said, is to develop alternative energy sources and “power our automobiles with something other than oil.”

Mr. Bush said he is “strongly committed” to using more ethanol, which is made from corn, as an alternative, drawing applause from his audience at the renewable fuels group. He said he wants to expand research into similar fuels made from wood chips and other plants or waste. Mr. Bush repeated his call for continued development of technology to use hydrogen as fuel.

The oil industry is one of the biggest donors to Republican election campaigns. In 2005, the industry gave 84% of $7 million to the Republicans, and the top 20 congressional recipients of the industry’s giving were all Republicans.