Washington (AFP) - The acting US ambassador to Ukraine, whose appearance to Congress built the Democrats' case for impeaching President Donald Trump, will step down at the end of the year, officials said.
William Taylor, a veteran diplomat, was sent to Kiev in June after the Trump administration controversially pulled out the US ambassador, Marie Yovanovitch.
Taylor's tenure will finish with the end of the year under terms of the Vacancies Act, in which appointees in acting position without Senate confirmation can serve 200 days, an official said.
Senator Robert Menendez, the top Democrat on the Senate Foreign Relations Committee, voiced alarm that Taylor's absence would leave a vacuum as Ukraine faces Russian-backed separatists.
Menendez also voiced concern that Secretary of State Mike Pompeo wanted Taylor out before the top US diplomat reportedly plans a visit to Ukraine in the new year.
"Your joint appearances with the ambassador in Kiev would also send a strong message of solidarity to our professional diplomatic service at a time when morale is historically low," Menendez said in a letter to Pompeo.
Taylor, who is the charge d'affaires at the Kiev embassy, was summoned to speak last month before a House committee looking into allegations that Trump held up nearly $400 million in aid to Ukraine.
Taylor told the House Intelligence Committee that Trump cared more about Ukraine starting an investigation into his domestic rival Joe Biden than in the country itself.
Taylor said he opposed the delay in assistance.
"Withholding security assistance in exchange for help with a domestic political campaign in the United States would be crazy," he said. "I believed that then and I believe it now."
Witnesses said that Trump was upset that Yovanovitch -- whom the president denounced in a call to his Ukrainian counterpart Volodymyr Zelensky -- was an impediment to starting an investigation into the role of Biden's son on the board of a gas company.