Executives from Detroit's Big Three reportedly called for "one national standard" for fuel economy and flexibility to align the regulations with consumer demand.

Ford chief executive Mark Fields has reportedly issued a dire warning to President Trump as the automotive industry faces ever-tightening fuel-efficiency regulations.

The executive told Trump that mpg rules could kill up to one million jobs in the US alone, according to quotes published by Bloomberg.

Leaders from the Detroit Big Three reportedly agreed that Trump's administration should push for harmonized regulations that take into account changing consumer tastes. The comments presumably refer to the spike in demand for high-riding SUVs and crossovers that tend to be less fuel efficient than less-popular small cars.

Fields sparred with Trump during the presidential campaign over Ford's plans to expand production in Mexico. After Trump won the election, executives from major US automakers took a more hopeful, collaborative tone and were among the first group of industry stakeholders to meet with the new President and discuss policy issues.

The Environmental Protection Agency appeared to fast-track its decision-making process and finalize 2025's tighter emissions regulations before Trump entered the White House. Trump has not yet publicly announced any specific plan to revise the standards.