CNN reported Monday that the one-time acting United States ambassador to China resigned from the State Department over President Donald Trump’s decision to withdraw the United States from the Paris Agreement on climate change, according to unnamed sources familiar with the decision.

Earlier Monday, SupChina editor-at-large John Pomfret wrote on Twitter that unnamed sources had said the official who resigned, David Rank, did so because he “couldn’t back Trump on climate.”

David Rank, no.2 @USEmbassyBJ, has resigned, sources say. He couldn't back Trump on climate. Rank had 27yr career including @USEmbassyKabul — John Pomfret 潘文 (@JEPomfret) June 5, 2017

Rank called a town hall meeting @USEmbassyBJ to say he could not deliver a demarche to the PRC govt over US withdrawal from @ParisAgreement https://t.co/mgkzns0YGm — John Pomfret 潘文 (@JEPomfret) June 5, 2017

Trump’s nominee for the ambassadorship, Iowa Gov. Terry Branstad, was sworn in as ambassador on May 24. The Senate confirmed him for the position on May 22.

Rank was a career foreign service officer who in January 2016 became deputy chief of mission at the U.S. embassy in Beijing, CNN reported.

“Mr. Rank made a personal decision,” an unnamed senior State Department official told the network. “We appreciate his years of dedicated service to the State Department.”

CNN noted the official did not name Trump’s Paris accord withdrawal as the explicit motivation for Rank’s resignation, but the network cited “several” unnamed “sources familiar with the decision,” who indicated, in CNN’s words, that the “departure is directly tied to Trump’s controversial move to pull out of the accord.”