Rank, a career Foreign Service officer of 27 years, told his staff that his conscience would not allow him to formally inform the Chinese about the United States decision to leave the climate accord.
The most senior U.S. diplomat in China has resigned over Donald Trump's rejection of the Paris climate accord, it was claimed, as the governor of California described the president's controversial decision as only a "temporary" setback in confronting global warming. Mr Rank has made a personal decision. "We appreciate his years of dedicated service to the State Department", US embassy spokeswoman Mary Beth Polley said.
He had been expected to continue in that role until Trump's pick for ambassador, former Iowa Gov. Terry Branstad, arrives.
A tweet from China expert John Pomfret quoted unnamed sources as saying that Rank had resigned as he could not support Trump's decision last week to withdraw from the Paris agreement.
He told The Associated Press on the sidelines of a clean energy conference in Beijing on Tuesday that China, Europe and US state governors will for now fill the gap left by the federal government's move to abdicate leadership on the issue.
According to a State Department official, who spoke on the condition of anonymity to be more candid, Rank was unwilling to deliver the demarche.
Rank becomes the second USA ambassador to publicly split with Trump in the past few days.
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"Despite China discussing for a long time about linking up with foreign markets, they are still at the stage of talking about it", added Ma, a deputy director general of the body, which is backed by the Chinese government. With Trump slow to make appointments many senior posts at the State Department are now filled by acting officials or vacant.
The acceptance of Chacon's resignation was first reported by the DiploPundit website.
It was not immediately clear whether he would be offered another post at the department.
The resignation was a display of the diplomat's unease with U.S. President Donald Trump's decision to exit the pact.
Chacon could not immediately be reached for comment.
Polley said the embassy informed China's foreign affairs ministry on Monday that Jonathan Fritz would be serving as charge d'affaires.
Former Ambassador Dan Feldman, Rank's supervisor for five years, called him a "quintessentially professional foreign service officer", adding that he was "thoughtful, calm, judicious, non-political" and someone "you want representing the USA government overseas".