The State Department denies Rank resigned over the Paris agreement as reported on Monday, Sputnik reported.
"Mr. Rank made a personal decision. We appreciate his years of dedicated service to the State Department," a senior department official told CNN.
Rank had been serving as acting ambassador since January 2016 until Trump's choice for ambassador to China arrived.
Trump’s latest move on climate change came after he signed an executive order on March 28 that directed agencies to rescind any pending rules and regulations related to the Climate Action Plan and instructed the US Environmental Protection Agency (EPA) to review and potentially withdraw Obama’s signature rule, the Clean Power Plan.