WASHINGTON, Jan. 2 - William Taylor, who was top American diplomat in Ukraine and an impeachment inquiry witness, has departed his post as chargé d'affaires ad interim in the country, USA Today reported.

Taylor, a West Point graduate and long-time diplomat, testified twice in the impeachment inquiry into President Donald Trump, providing key testimony. Taylor succeeded ousted Ambassador Marie Yovanovitch in June when she was unexpectedly removed from her position by the White House.

The embassy posted a farewell message on New Year's Eve from Taylor that reads he knew he would be serving in the position for a "limited period of time."

Taylor, who previously served as ambassador to Ukraine from 2006 to 2009, emphasized the "strong support" the U.S. has for Ukraine that is "bipartisan support," and declared that "The time since June has been a great one, it's an exciting time to be in Ukraine."

The U.S. Embassy in Ukraine stated Thursday that Kristina Kvien has taken over Taylor's role. She was serving as deputy chief of mission at the embassy.

In a video message posted Thursday, Kvien said that "While the embassy's leadership is changing, our policy of strong support for Ukraine remains steady."

"Our embassy team will continue to partner closely with the Ukrainian government and civil society in support of Ukraine's sovereignty and territorial integrity and in support of reforms that will help Ukraine build its prosperous European future," she continued.

Trump yanked Yovanovitch from her post in April, after his personal lawyer, Rudy Giuliani, targeted her with what other diplomats described as a "smear" campaign.

Taylor emphasized in his testimony that an irregular backchannel existed regarding policy in Ukraine, and said that after security assistance was held up, "The irregular policy channel was running contrary to the goals of longstanding U.S. policy."

Taylor told lawmakers that he had heard from a Ukraine official that Ukrainian leader Volodymyr Zelenskiy "did not want to be used as a pawn in the U.S. re-election campaign."

He also said it was "crazy to withhold security assistance for help with a political campaign."

The inquiry built upon Trump’s phone call on July 25 to Zelenskiy, when he urged the investigation of former Vice President Joe Biden while withholding nearly $400 million in congressionally-approved military aid. (us/ez)