The top U.S. diplomat in Ukraine, William Taylor, will be leaving his post next month, following a short term marked by the impeachment inquiry into President Donald Trump.
In an e-mail to The New York Times on December 17, Taylor said he would step down in early January because his temporary appointment to Ukraine in June is set to expire.
The Trump administration "will nominate a permanent ambassador soon," he wrote, without elaborating.
Earlier media reports quoted unidentified U.S. officials as saying that Taylor, the charge d'affaires at the Kyiv embassy, would leave his post by the end of the month or in early January.
He will be replaced on an interim basis by his current deputy, Kristina Kvien, according to AP.
Taylor's testimony before the Democratic-led House Intelligence Committee last month helped build the case for impeaching Trump, who is accused of pressuring Ukrainian President Volodymyr Zelenskiy to investigate the U.S. president's political opponent Joe Biden by withholding military aid.
The diplomat said he thought it was "crazy" to withhold military aid that Ukraine needed to fight Russia-backed forces in its eastern provinces.
Taylor was sent to Ukraine after the State Department unexpectedly recalled Ambassador Marie Yovanovitch in May.
He had previously served as U.S. Ambassador to Ukraine in 2006-2009.