Democrat Dianne Feinstein of California tried to add the plan to a broad energy bill being debated by the committee. The panel voted against it, 15 to 7.

Supporters said closing the so-called "SUV loophole" would reduce U.S crude oil imports, cut down on polluting emissions spewed by vehicles and save consumers money at the pump.

Opponents said imposing a higher fuel standard would place further burdens on US automakers that are already suffering financially, endangering thousands of high-paying jobs. They also said the government should not dictate what vehicles consumers buy.

"I think mothers and fathers can make those decisions themselves," said Republican George Allen of Virginia.

However, Feinstein pointed out that consumers are on waiting lists to buy more fuel-efficient hybrid vehicles made by Japanese automakers, while US companies are stuck with growing inventories of gas-guzzling SUVs.

"They (US automakers) have essentially refused to listen to the marketplace," she said. "Toyota is going to eat their lunch."

Ford Motor Co and General Motors Corp. have seen demand for their once highly-profitable SUVS plunge in recent months as retail gasoline prices rose to record highs.

Chairman Pete Domenici of New Mexico said another provision in the bill would require the president to find ways to cut US oil demand by 1 million barrels per day by 2015.

US oil demand averages about 21 million barrrels per day, with imports accounting for 3 out of every 5 barrels consumed. Gasoline use makes up 40 percent of total oil demand.

Separately, Domenici said he expects lawmakers to offer an amendment to the energy bill to boost annual ethanol production possibly to 8 billion gallons. The corn-based additive, which has broad support among lawmakers from farm states, helps stretch US gasoline supplies and makes fuel burn cleaner.

Energy legislation passed by the US House recently would set an annual ethanol mandate of 5 billion gallons by 2012.

On Wednesday, the Senate committee approved provisions in the energy bill related to coal, hydrogen, and energy research and development. The bill would provide $200 million annually for nine years to promote clean coal technologies.

The panel will meet again on Thursday to vote on energy efficiency issues, improving the reliability of the US power grid and other electricity matters.

The Thursday session will not be disrupted by a showdown between Senate Democrats and Republicans over the White House's stalled judicial nominees, a committee aide said. On Wednesday, Democrats said they would use a procedural move to bar all Senate committees from meeting more than two hours a day.

Domenici had already planned to limit the energy committee's business to two hours.

Domenici said he wants the committee to approve a final energy bill next week and send it to the full Senate for a vote next month.