Donald Trump, the presumptive Republican presidential nominee, has promised to roll back some of America's most ambitious environmental policies, actions that he said would revive the ailing US oil and coal industries and bolster national security.
Among the proposals, Trump said he would pull the US out of the UN global climate accord, approve the Keystone XL oil pipeline from Canada, and rescind measures by President Barack Obama to cut US emissions and protect waterways from industrial pollution.
"Any regulation that's outdated, unnecessary, bad for workers or contrary to the national interest will be scrapped and scrapped completely," Trump told about 7700 people at the Williston Basin Petroleum Conference in Bismarck, the capital of oil-rich North Dakota.
"We're going to do all this while taking proper regard for rational environmental concerns."
It was Trump's first speech detailing the energy policies he would advance if elected president. He received loud applause from the crowd of oil executives.
The comments painted a stark contrast between the New York billionaire and his Democratic rivals for the White House, Hillary Clinton and Bernie Sanders, who advocate a sharp turn away from fossil fuels and towards renewable energy technologies to combat climate change.
Trump slammed both rivals in his speech, saying their policies would kill jobs and force the US "to be begging for oil again" from Middle East producers.
Trump's comments drew quick criticism from environmental advocates, who called his proposals "frightening".
"Trump's energy policies would accelerate climate change, protect corporate polluters who profit from poisoning our air and water, and block the transition to clean energy that is necessary to strengthen our economy and protect our climate and health," said Tom Steyer, a billionaire environmental activist.
But industry executives cheered the stance.
"It's simple. If Trump wins, oil field workers will be happy. If Clinton wins, oil workers will be unhappy," said Derrick Alexander, an operations manager at oilfield services firm Integrated Productions Services.
Trump hit Clinton hard in his speech, saying the former secretary of state would be more aggressive than Obama on regulations. He repeated several times Clinton's March comments that her policies would put coalminers out of work.
"Hillary Clinton's agenda is job destruction," Trump said.
Trump said slashing regulation would help the US achieve energy independence and reduce reliance on Middle Eastern producers. "Imagine a world in which oil cartels will no longer use energy as a weapon," he said.
The US currently produces about 55 per cent of the oil it uses, with another quarter of the total coming from Canada and Mexico, and less than 20 per cent coming from OPEC, according to US Energy Department statistics.
Energy Department figures show the US has been the world's top producer of petroleum and natural gas for the past four years.
Trump's advisers have said they suggested Trump examine the role of OPEC in the global oil price slump since 2014, which has contributed to the demise of a handful of smaller US oil companies.
Saudi Arabia and other OPEC members have declined to cut production to support prices.
Until Thursday, Trump had been short on details of his energy policy. He has said he believes global warming is a hoax, that his administration would revive the US coal industry, and that he supports hydraulic fracturing - an environmentally controversial drilling technique that has triggered a boom in US production.
Earlier this month, he told Reuters in an interview that he would renegotiate "at a minimum" the UN global climate accord agreed by 195 countries in Paris last December, saying he viewed the deal as bad for US business.
He took that a step further in North Dakota. "We're going to cancel the Paris climate agreement," he said.
Trump also promised he would invite Canadian pipeline company TransCanada to reapply to build the Keystone XL pipeline into the US, reversing a decision by Obama to block the project over environmental concerns.
"I want it built, but I want a piece of the profits," Trump said. "That's how we're going to make our country rich again."
