Updated

Ten states, led by California, sued the federal government Tuesday to try to force the Bush administration to strengthen gas mileage requirements for sport utility vehicles and pickup trucks.

The lawsuit contends the National Highway Traffic Safety Administration failed to conduct a thorough analysis of the environmental benefits of fuel economy regulations and the impact of gasoline consumption on climate change.

"The federal agency has ignored the law that requires integrating environmental impacts into their standard-setting," California Attorney General Bill Lockyer said in an interview with The Associated Press.

The states filed a petition for review with the 9th U.S. Circuit Court of Appeals in San Francisco. The action follows the release of a government rule in late March setting tighter gas mileage rules for pickups, SUVs and vans covering the 2008-2011 model years.

The Bush administration said the program, based on the vehicle's size, was expected to save 10.7 billion gallons of fuel over the lifetime of the vehicles sold during that period.

NHTSA spokesman Rae Tyson defended the rulemaking process, saying the agency conducted a thorough analysis of fuel-saving technologies while balancing the need to raise standards with safety and economic ramifications.

"We're confident that we went through a very rigorous process in writing the final light truck standard and we're confident that it will get upheld in court," Tyson said.

Charles Territo, a spokesman for the Alliance of Automobile Manufacturers, declined comment on the lawsuit. The trade group, which represents nine automakers, has said the new standards will be a challenge but they have developed alternative-fuel vehicles and more than 100 vehicles earning at least 30 miles per gallon.

Plans for the lawsuit were first reported by The New York Times.

Amid rising gas prices and worries about energy independence, the administration asked Congress last week to give it the authority to change fuel economy standards for passenger cars.

Environmentalists have expressed disappointment with the light truck rule that would lead to a fleetwide average of 24 mpg by 2011. The program will be phased in through 2010, with automakers having the option of complying under the old system until the new rules take full effect in 2011.

"The proposed upgrade in fuel economy standards is a complete sham and a gift to the auto industry," said Connecticut Attorney General Richard Blumenthal.

Blumenthal said in an AP interview that the analysis was "fundamentally flawed" and the new regulations failed "to consider the dangerous impact of gasoline consumption on climate change," allowing larger vehicles to be built with greater weight and less fuel economy.

The 10 states include California, Connecticut, Maine, Massachusetts, New Jersey, New Mexico, New York, Oregon, Rhode Island and Vermont. The District of Columbia and New York City were also plaintiffs.