Republican presidential nominee Donald Trump has said he would “cancel” the Paris climate deal.
More than 195 countries pledged to reduce carbon emissions in a landmark agreement last year.
The billionaire businessman has said before there is no evidence that humans are responsible for climate change.
During a speech at an oil industry conference in North Dakota, he called for more fossil fuel drilling and fewer environmental regulations.
“Any regulation that’s outdated, unnecessary, bad for workers or contrary to the national interest will be scrapped and scrapped completely,” Mr Trump said.
“We’re going to do all this while taking proper regard for rational environmental concerns.”
Before this speech, he had said he would “renegotiate” the global agreement involving nearly all countries, but this time he went further and said the US would pull out.
The climate change deal is “bad for US business”, he said.
Mr Trump also said he would approve the Keystone XL oil pipeline from Canada.
On Thursday, he officially became the presidential nominee for his party, surpassing the 1,238 delegates required.
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