One of President Trump’s former aides said Monday that the U.S. will pull out of the landmark Paris climate pact within the coming “days.”

Myron Ebell, who helped the Trump administration’s Environmental Protection Agency transition, told reporters that Trump was “determined” to undo Barack Obama’s climate change initiatives.

“I expect Donald Trump to be very assiduous in keeping his promises, despite all of the flack he is going to get from his opponents,” Ebell said, according to London's The Independent. “He could do it by executive order tomorrow, or he could wait and do it as part of a larger package. There are multiple ways and I have no idea of the timing.”

Ebell, a climate change skeptic, helped review the EPA’s work during the Trump transition.

The U.S. is one of 194 countries who signed the Paris climate agreement in April 2016. The pact aimed to “stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system."

Trump, who once stated that climate change was a hoax created by the Chinese, previously stated that he would keep an open mind on the climate deal.

Trump’s secretary of state nominee Rex Tillerson, a former ExxonMobil executive, said during his confirmation hearing that the U.S. would be “better served by being at that table than leaving that table.” Ebell said Tillerson would lose the fight over leaving the Paris agreement.

“…the president was elected and Rex Tillerson was appointed by the president, so I would guess that the president would be the odds-on favorite to win any disagreement over climate policy."

Pulling out of the Paris deal might be the more difficult route. A Trump transition official told Reuters last year the administration could opt to pull out of the 1992 parent treaty of the deal – which would void the U.S.’ involvement in both agreements.

European Commission Vice President Maros Sefcovic, who helped broker the Paris agreement, told Reuters he hoped Trump would agree to keep the U.S. in the deal.

"I wouldn't hide that in discussion with our partners; there is a lot of anxiety over future U.S. policies.

"If the (U.S) administration decides to go in a different direction, I think sooner or later they will have to come back to the realization that climate change is happening."

Any country that leaves the Paris deal would have to wait four years to get back in.

Click for more from the Independent.