BEIJING (AP) — The U.S. ambassador to China appears to be leaving his post, based on tweets posted Monday by Secretary of State Mike Pompeo.

Pompeo thanked Ambassador Terry Branstad on Twitter for his more than three years of service. There was no immediate confirmation from the State Department.

“Ambassador Branstad has contributed to rebalancing U.S.-China relations so that it is results-oriented, reciprocal, and fair,” Pompeo wrote.

Branstad was embroiled in a recent controversy when China’s official People’s Daily newspaper rejected an opinion column that he had submitted. It wasn’t clear if his apparent departure was related to the piece.

Pompeo tweeted last week that China’s ruling Communist Part refused to run Branstad’s op-ed while the Chinese ambassador to the United States “is free to publish in any U.S. media outlet.”

Chinese foreign ministry spokesperson Zhao Lijian responded that Branstad’s article was “full of loopholes, seriously inconsistent with facts and wantonly attacks and smears China.”

The U.S. Embassy had contacted the People’s Daily on Aug. 26 about the piece, asking that it be printed in full without any edits by Sept. 4.

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