President Donald Trump has ordered a review of US vehicle fuel-efficiency standards put in place by the Obama administration, handing a victory to auto industry executives and provoking criticism from Democrats and environmental groups.

Key points: Car industry has been seeking to reopen the fuel efficiency rules put in place by Obama

Car industry has been seeking to reopen the fuel efficiency rules put in place by Obama Trump says he expects automakers to hire more Americans in return

Trump says he expects automakers to hire more Americans in return Ten state attorneys general say they will fight attempts to weaken fuel efficiency rules

In a move widely seen as a preamble to loosening fuel standards, Mr Trump told an audience of cheering union workers he would "ensure that any regulations we have protect and defend your jobs, your factories," and promised he would encourage growth in the US auto sector.

"The assault on the American auto industry is over," Mr Trump said, standing in front of a banner that read "Buy American-Hire American".

Loading

Mr Trump added that the White House was "setting up a task force in every federal agency to identify and remove any regulation that undermines American auto production".

The backdrop and message underscored Mr Trump's efforts to lock down support in industrial states such as Michigan that put him in the White House.

At a roundtable with industry leaders Mr Trump made clear he expected automakers to hire more Americans in return, a theme that dominated his election campaign.

"We're going to do some wonderful work with you, but you're going to have to help us with jobs," he said.

Growth prioritised over environmental concerns

Reopening the fuel efficiency rules put in place by Democratic President Barack Obama days before he left office is one of the top items on the industry's agenda.

Automakers, through their lobbying groups, have said the Obama rules were too expensive and could cost American jobs.

"These standards are costly for automakers and the American people," Environmental Protection Agency Administrator Scott Pruitt said.

After one participant in the meetings mentioned environmental concerns, Mr Trump said he agreed but did not want an "extra thimbleful of fuel" to get in the way of growth.

Automotive industry executives and lobbying groups were quick to praise the administration's announcement.

"The Trump administration has created an opportunity for decision-makers to reach a thoughtful and coordinated outcome predicated on the best and most current data," said Mitch Bainwol, chief executive of the Alliance of Automobile Manufacturers, an industry lobbying group.

Automakers have signalled they want the government to give manufacturers more credit toward achieving fuel efficiency targets for technologies such as "stop-start" systems that shut down a car's engine at a traffic light.

Regulators should also look at whether ride hailing and vehicle-to-vehicle communications systems designed to prevent accidents and alleviate road congestion could be counted toward the industry's greenhouse gas emissions goals, the automaker group proposed in comments to the EPA last year.

Critics like Democratic US Senator Edward Markey of Massachusetts said Mr Trump's move could hurt consumers.

"Filling up their cars and trucks is the energy bill Americans pay most often, but President Trump's roll-back of fuel economy emissions standards means families will end up paying more at the pump," Mr Markey added.

A group of 10 state attorneys general led by California and New York said they would fight attempts to weaken the rules.

Reuters