Former U.S. Ambassador to Ukraine Marie Yovanovitch testifies during the second public impeachment hearing of President Donald Trump in Washington, DC, November 15, 2019. (Photo: AP)

Former U.S. Ambassador to Ukraine Marie "Masha" Yovanovitch, who played a key role in the House hearings on President Donald Trump's impeachment last November, has retired from the State Department, according to U.S. media reports.

She was removed from her position as a U.S. diplomat in May 2019 after a targeted campaign against her led by the president. She later stated her struggles of how she had fought corruption in Ukraine and how the Trump administration abruptly removed her in a televised impeachment hearing.

It is still not clear when exactly Yovanovitch retired, yet CNN reports said it was sometime in the last two weeks.

The former U.S. diplomat leaves after more than 30 years in foreign service. The U.S. State Department has yet to comment on the matter.