Elon Musk says that he’ll have “no choice” but to withdraw from the advisory councils he’s currently serving for President Trump, should Trump decide to step back from the Paris climate agreement as he’s reportedly been considering. Musk tweeted the ultimatum on Wednesday, in response to a question from a follower on the social network.

Will have no choice but to depart councils in that case — Elon Musk (@elonmusk) May 31, 2017

Musk currently sits on Trump’s economic and manufacturing advisory councils, and defended his choice to remain on the council when challenged for his participation following Trump’s immigration bans, which were broadly opposed by Silicon Valley and technology companies, including Tesla . At the time, Musk reasoned that disagreement should not be a reason to distance himself from a position where he could potentially influence the president’s thinking.

The Paris agreement, which was first adopted by UN consensus agreement in 2015, sets specific goals for reducing climate impact resulting from greenhouse gases through international co-operation. Axios first reported that Trump was going to pull the U.S. out of the Paris agreement, and the president tweeted earlier today that he’ll reveal his decision officially over the next few days.

Musk previously noted that he “spoke directly with The President about Paris,” tweeting that he was “cautiously optimistic” that Trump would see things his way and agree that the right decision was to stick with the agreement just last week. Again, Musk noted that he’s not sure which way Trump will ultimately swing, but his statement of intent about what will happen if the U.S. pulls out is pretty straightforward.