A former aide to Donald Trump’s transition into president said that Trump could issue an executive order to remove the United States from the Paris Agreement on climate change within “days,” according to London-based The Independent.

The Global Warming Policy Foundation, a think tank that believes the climate change issue is “not yet settled,” hosted an event Monday afternoon (January 30), where climate skeptic Myron Ebell, who led the EPA transition team, spoke. He was clear, The Independent reports, that the president would pull the United States from the landmark international agreement set to curb global carbon emissions and mitigate climate change impacts.

Ebell wasn’t clear, however, on how this would happen: “[Trump] 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.”

In November, in an interview with The New York Times, the then-president elect said he had an “open mind” to the agreement. And Trump’s nominee for secretary of state, former ExxonMobil CEO Rex Tillerson, said that the U.S. would be “better served” by sticking with the other 193 signatories to the accord during his Senate hearing on January 11.

Ebell has been making statements regarding this administration’s actions before, including when Trump froze EPA grants and contracts January 23. If Trump does, in fact, pull from the international agreement, it would be his latest move against environmental regulation.

In his first week in office, the president signed executive orders and presidential memorandums to expedite the construction of energy projects, including the Keystone XL and Dakota Access pipelines; ordered federal agencies, including the EPA, to pause public comment and social media use; and indicated that any scientific findings would need to be reviewed on a “case by case basis” before publication.

(H/t The Independent)