SpaceX and Tesla Chief Executive Elon Musk said on Twitter Wednesday that he would leave President Donald Trump’s councils should the United States withdraw from The Paris Agreement on climate change.

“Don’t know which way Paris will go, but I’ve done all I can to advise directly to POTUS, through others in WH & via councils, that we remain,” he wrote on Twitter. “Will have no choice but to depart councils in that case.”

The Paris Agreement limits the emission of greenhouse gas from signatory nations. Reports emerged Wednesday afternoon that Trump would in fact withdraw the United States from the treaty, though an official announcement has not yet been made.

Musk, a member of Trump’s manufacturing jobs council and his strategic and policy forum, said such a move would be unacceptable to him.