The Bush administration is reviewing a proposal to require auto manufacturers to make a modest improvement in the fuel efficiency of sport-utility vehicles and light trucks at a time of heightened concern about U.S. dependence on Middle East oil.

The National Highway Traffic Safety Administration said yesterday that it had submitted a proposal to the White House earlier this month to raise the fuel efficiency standards of SUVs, beginning with 2005 models. The administration is expected to announce a final rule by April 1, to give automakers time to make the necessary changes in engine and body designs.

The Wall Street Journal reported that the NHTSA's draft recommendation would raise fuel efficiency standards by roughly a half a mile per gallon each year in model years 2005 through 2007, to 22.2 miles per gallon in 2007. NHTSA, a Transportation Department agency with authority to establish fuel economy standards, based its plan on data submitted by Detroit's Big Three automakers.

Claire Buchan, a White House spokeswoman, declined to comment on the details of the proposal but stressed that no decision has been reached. "Any decision will be made consistent with the administration's policy . . . that we believe fuel efficiency should be increased in a way that protects lives and jobs," she said.

Rep. Edward J. Markey (D-Mass.), a senior member of the House Energy and Commerce Committee, and several environmental groups criticized the proposal as inadequate in the face of a possible war with Iraq that could disrupt Middle East oil supplies. "The Bush administration claims to be striving for energy independence -- yet this proposed increase in fuel economy for SUVs doesn't even come close to what could be achieved using technologies that are already available," Markey said.

However, Kevin Mills, director of Environmental Defense's pollution prevention alliance, said, "Compared to the last CAFE rulemaking, an increase of this level would be a significant step forward."

Even small changes in U.S. driving habits can have a significant impact on domestic oil consumption and international markets. Congress established the corporate average fuel economy targets for cars and trucks in 1975 in response to the Arab oil embargo. But the auto industry has increasingly resisted the CAFE system. Congress has routinely imposed a freeze on CAFE rulemaking, and the House and Senate rejected measures to stiffen fuel efficiency requirements during deliberations over proposed energy legislation last year and this year. But Congress late last year lifted the rulemaking ban, enabling NHTSA to develop the latest proposal.