Environmentalists and consumer groups asked President Trump's Environmental Protection Agency on Wednesday to keep in place fuel efficiency standards for new cars and trucks created by the Obama administration.

Automakers, meanwhile, continued to press for relief from the rules, arguing low gasoline prices have weakened consumer demand for hybrid-electric cars and smaller fuel-efficient models.

The EPA hosted an all-day meeting on the Trump administration's proposal to rollback rules that would have required automakers to nearly double the average fuel economy of new cars and trucks to 54.5 miles per gallon by 2025.

In March, Trump ordered a review of the standards, and Wednesday's meeting was the only public forum for all sides to make their arguments. The EPA is taking written comment through Oct. 5.

"I'm here today to call on EPA to continue the tremendous success and leadership of its clean cars program, and to condemn the current administration's signals that it will recklessly weaken these standards and shortchange EPA's role," said Martha Roberts, senior attorney for the Environmental Defense Fund's U.S. Climate Legal and Regulatory program, in her testimony at the public meeting in Washington D.C.

Automobile manufacturers counter the Obama EPA made the decision to impose more stringent fuel efficiency rules in 2012 before a congressionally mandated 2017 midterm review of the vehicle rules.

Less fuel efficient SUVs and light trucks have become more popular in recent years, meaning manufacturers are having difficulty hitting the federal vehicle targets, the auto industry argues.

"A lot has changed since 2012," said Julia Rege of Global Automakers, a group representing automakers including Toyota and Hyundai. "Gas prices remain at near historic lows, customers are choosing trucks over cars by large margins, and overall sales appear to be throttling back from the record pace of the last two years. That is why we need to give manufacturers the flexibility to each pursue the most effective ways to achieve the aggressive targets and still meet the needs of their respective customers."

While automakers have said the standards could add at least $2,000 to the sticker price of a vehicle, consumer groups said Wednesday the Obama standards would save consumers enough money on gasoline to offset price increases for new technology.

"The gradual improvements to fuel economy and emission standards in place today are part of a practical and tested program to reduce fuel consumption, improve consumer choice, protect public health and save consumers trillions of dollars," said Jack Barnett, research assistant for Consumers Union.

The meeting also showcased a fight between states, led by California, and the Trump administration over the proposed weakening of the fuel efficiency rules.

Annette Hebert, an official with the California Air Resources Board, warned the state could withdraw from the nationwide vehicle emissions program if the EPA limits the regulations.

California has set its own rules that go beyond the national standards, and other states can follow those instead.

In June, New York's Democratic attorney general, Eric Schneiderman, and 12 other state law enforcement officials said they would sue the Trump administration if it rolled back vehicle emission rules.

"Science doesn't change based on election results," Hebert said, referring to Trump's election.

Automakers said Wednesday they want California and the Trump administration to compromise on new national standards in order to provide more certainty in the marketplace and eliminate the prospect of a legal battle.

"Anything that falls short of one program does not provide a consistent path forward," Rege said.

Robbie Diamond, CEO and president of Securing America's Future Energy, insists there is a deal to be had that accommodates the concerns of both sides.

"It is in no one's interest to have competing standards between our largest state and the rest of the country," Diamond told the Washington Examiner in an interview after the meeting. "Because oil prices are volatile, and because of technology challenges, it's in automakers short-term interest to have flexibility in the standards. And there is a way to do that while meeting the long-term trajectory of reduced oil use and technological innovation."