Trump will be joined in the Oval Office mid-afternoon by the CEOs of Ford and Stellantis, and a General Motors' official, to announce the rollback -- with the presence of the so-called "Big Three" automakers signaling critical industry buy-in.

"Joe Biden's fuel efficiency regulations would have raised the cost of a new vehicle by $1,000," the White House said on X, adding that Trump's reset would save Americans $109 billion.

The reset concerns Corporate Average Fuel Economy (CAFE) standards, which date back to 1975, when the United States was hit by the Arab oil embargo, and regulate how far vehicles must travel on a gallon of fuel.

The full extent of the move wasn't immediately clear.

But the Trump administration has repeatedly signaled its opposition to efficiency increases enacted under Biden. The latter sought to boost it eight percent annually for model years 2024-2025 and 10 percent annually for model year 2026 -- reaching more than 50 miles per gallon by 2031.

In a proposed rule issued in June, the Trump administration argued that Biden officials had improperly factored in electric and hybrid vehicles when devising those targets, saying the standards would be unattainable for gasoline-powered cars and would effectively force a shift in the market.

Trump has railed against what he calls an EV "mandate." Republicans in Congress have repealed clean-energy tax credits in a major tax and spending bill, and targeted California's ability to set its own vehicle-emission limits.

"As America's largest auto producer, we appreciate President Trump's leadership in aligning fuel economy standards with market realities," Ford CEO Jim Farley said in a statement.

"We can make real progress on carbon emissions and energy efficiency while still giving customers choice and affordability. This is a win for customers and common sense."

But Gina McCarthy, a former senior official under Biden and Barack Obama, said the move would ultimately harm the auto industry by slowing its shift to electric vehicles and worsen climate change.

"If there's one thing you can count on, it's that this administration will never act in the best interest of our health or the environment," she said.

"The rest of the world will continue to innovate and create cleaner cars that people want to buy and drive, while we're forced to sit in our clunkers, paying more for gas, and pumping out more tailpipe emissions."