More than three dozen conservative and free-market groups pressed President Trump on Monday to exit from the Paris climate change agreement and not renege on the promise he made during his campaign.

"The undersigned organizations believe that withdrawing completely from Paris is a key part of your plan to protect U.S. energy producers and manufacturers from regulatory warfare not just for the next four years but also for decades to come," a letter sent to Trump on Monday read, signed onto by 38 groups. "We will strongly support your decision to keep your campaign commitment to withdraw from the Paris Climate Treaty."

The groups leading the letter are the Competitive Enterprise Institute and the American Energy Alliance. Senior members of both groups were the heads of Trump's transition teams for the Environmental Protection Agency and the Energy Department respectively.

"The Paris Climate Treaty is an all pain for no gain agreement that will produce no measurable climate benefits and exacerbate energy poverty around the globe," said Myron Ebell, former head of Trump's EPA transition team and director of CEI's Center for Energy and Environment.

The letter is being sent as Trump is set to convene with week with his senior advisers and members of his Cabinet to hash out a decision on the Paris climate agreement.

The groups signed onto the letter are concerned that many of Trump's advisers are supportive of the idea of not exiting from the agreement, believing they can renegotiate the deal toward an end that agrees with Trump's "America First" agenda. But the groups warn that such an approach would backfire.

"Some officials in your administration are relying on recent statements from former Obama administration officials that the U. S. can withdraw its [previous commitment under the accord] and submit a new [target] that makes far less ambitious commitments to reduce greenhouse gas emissions," the letter stated.

But the "clear language of Article 4 of the Paris Climate Treaty contradicts that claim", stating that "A Party may at any time adjust its existing nationally determined contribution with a view to enhancing its level of ambition." That means the only change the U.S. can make is one that increases its obligations to reduce emissions and fossil fuel use.

"Even if the U. S. were to be cleared by UN officials to submit a less ambitious [goal], this is not the end of the threats posed by the Paris Climate Treaty to your pro-energy agenda and to the economic future of our country," the letter stated. The deal requires that each country submit more ambitious goals every five years "in perpetuity," which "cannot be wished away by those who argue that the U.S. should keep a seat at the negotiating table in order to advocate for fossil fuels," the letter added.

Some of the largest coal companies in the U.S. have been pressing Trump to remain a party to the agreement in order to help them renegotiate a deal that favors clean coal technologies. Trump also supports clean coal.

The groups argue that there are really only three options for Trump. First, he can submit the treaty to the Senate for a vote. "Submitting the treaty to the Senate would return us to and restore the proper constitutional method for treaty-making and require a future administration to go through proper procedures if it were to attempt to rejoin the treaty," the letter explained.

The groups refer to the agreement as a treaty, although the Obama administration argued it is not binding. Under the law, all international treaties must be approved by the Senate. And with a Republican majority in the Senate, it has a good chance of being voted down.

"Second, you could withdraw from the underlying UN Framework Convention on Climate Change," the letter said. "This action would also achieve your commitment to 'stop all payments of the United States tax dollars to UN global warming programs,' including the Green Climate Fund, which is a part of the UNFCCC." The green climate fund is designed to help small, developing nations deal with the challenges posed by climate change, such as sea-level rise.

Third, Trump could state that he intends to withdraw from the agreement, base on the four-year schedule that the deal specifies for nations wishing to leave the agreement. In that time, Trump would continue the process of repealing the regulations that the Obama administration submitted as part of its commitment.

But there is a risk with the third option. "This option is the least preferable because it runs the risk of legitimizing the Obama administration's false claim that the treaty is merely an executive agreement," the letter reads. It could also give environmental groups time to mount a legal case that could get the courts to reverse Trump's efforts to rescind Obama's climate rules on the grounds that it counters the goals of the Paris deal.

The Heartland Institute, Americans for Tax Reform, Americans for Prosperity, Heritage Action for America and the Heritage Foundation were some of the other groups that signed onto the letter.