A senior adviser to Secretary of State Mike Pompeo has resigned amid plunging morale at the State Department over what is seen as the top US diplomat’s failure to support officials caught up in the Ukraine controversy, according to a report.

Michael McKinley was serving as ambassador to Brazil when Pompeo appointed him as a policy adviser in May 2018, according to the Washington Post, which first reported the resignation.

McKinley, who also served as ambassador to Afghanistan, Colombia and Peru, declined to comment Thursday evening. Pompeo was expected to issue a statement Friday about his departure, the newspaper reported.

The resignation comes as Pompeo faces mounting pressure from House investigators after it emerged that he was on the line when President Trump asked Ukrainian President Volodymyr Zelensky to probe former Vice President Joe Biden and his son Hunter.

There is no evidence of any wrongdoing by the Bidens in Ukraine.

Among the various issues on which he played a role, McKinley has been closely involved in administration policy on Venezuela, Mexico, Southeast Asia and Afghanistan, where Trump last month canceled US peace negotiations with the Taliban, according to the paper.