Washington DC - President Donald Trump on Thursday announced the easing of curbs on a group of powerful greenhouse gases commonly found in refrigerators and air conditioners.

Republican Trump slammed the "ridiculous" rules introduced by his Democratic predecessor, President Joe Biden, on super-pollutants known as hydrofluorocarbons.

Trump said the move would reduce the cost of living for US consumers. His approval ratings are plummeting as disruption to oil supplies from the Iran war drives up prices.

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Speaking in the Oval Office, Trump said he was "officially terminating the Biden administration's ridiculous regulations imposing costly requirements on refrigerators and air conditioners."

"It's ridiculous, unnecessary, and costly, and actually makes the machinery worse," the billionaire president added.

Trump's administration is extending deadlines for grocery and other companies to phase out the use of HFCs under a 2023 law, the Environmental Protection Agency said in a statement.

It will also amend a 2024 act so that it exempts all road refrigerant appliances used to transport goods from new leak requirements for HFCs, it said.

Surrounded by company executives as he sat at his Oval Office desk, Trump said there would be "no negative impact" from the changes.

"There's no environmental concern," he said.

EPA chief Lee Zeldin said the actions put the brake on a "rushed, frantic, reckless sprint" by previous administrations to phase out HFCs. The move would save Americans $2.4 billion in regulations on the greenhouse gases that firms pass on to consumers, the EPA said.

The cost of living promises to be the key issue in crucial US midterm elections in November, in which Trump's Republicans will be fighting to keep control of Congress.

A New York Times/Siena poll released Monday put Trump's approval rating at 37%, the lowest of his second term, with 64% of voters saying the Iran war was a mistake and the same proportion disapproving of his handling of the economy.