US President Donald Trump speaks between Vice President Mike Pence (L) and EPA Administrator Scott Pruitt prior to signing an executive order on "Energy Independence," eliminating Obama-era climate change regulations, during an event at the Environmental Protection Agency (EPA) headquarters in Washington, US, March 28, 2017. [Photo/Agencies]

Flanked by coal miners and coal company executives, Trump proclaimed his "Energy Independence" executive order at the headquarters of the Environmental Protection Agency.

The move drew swift backlash from a coalition of 23 states and local governments, as well as environmental groups, which called the decree a threat to public health and vowed to fight it in court.

The order's main target is former President Barack Obama's Clean Power Plan, which required states to slash carbon emissions from power plants - a key factor in the United States' ability to meet its commitments under a climate change accord reached by nearly 200 countries in Paris in 2015.

Trump's decree also reverses a ban on coal leasing on federal lands, undoes rules to curb methane emissions from oil and gas production and reduces the weight of climate change and carbon emissions in policy and infrastructure permitting decisions. Carbon dioxide and methane are two of the main greenhouse gases blamed by scientists for heating the earth.

"I am taking historic steps to lift restrictions on American energy, to reverse government intrusion and to cancel job-killing regulations," Trump said at the EPA.

The room was filled with miners, coal company executives and staff from industry groups, who applauded loudly as Trump spoke.

Shares in US coal companies edged higher in response.

The wide-ranging order is the boldest yet in Trump's broader push to cut environmental regulation to revive the drilling and mining industries, a promise he made repeatedly during the 2016 presidential campaign.

Energy analysts and executives have questioned whether the moves will have a big effect on their industries, and environmentalists have called them reckless.

"I cannot tell you how many jobs the executive order is going to create, but I can tell you that it provides confidence in this administration's commitment to the coal industry," Kentucky Coal Association president Tyler White told Reuters.

Environmental groups heaped scorn on Trump's order, arguing it was dangerous and went against the broader global trend toward cleaner energy technologies. A coalition of mostly Democrat-led states and local governments issued a statement saying they would oppose the order in court.

"We won't hesitate to protect those we serve — including by aggressively opposing in court President Trump's actions that ignore both the law and the critical importance of confronting the very real threat of climate change," the coalition, led by New York Attorney General Eric Schneiderman, said in astatement.

The coalition includes states such as California, Massachusetts and Virginia, as well as cities including Chicago, Philadelphia and Boulder, Colorado.