Former U.S. Sen. Jeff Flake formally stepped into his new position as U.S. ambassador to Turkey on Wednesday. 

Flake is a former Republican lawmaker who endorsed U.S. President Joe Biden's 2020 run for the White House. He served in the U.S. Senate from 2013 to 2019 and in the U.S. House of Representatives from 2001 to 2013.

He takes up the position at a difficult time for U.S.-Turkish relations. His appointment also comes amid threats of sanctions against Russia by the United States and its allies over concerns that Russia may be planning to invade Ukraine

Flake retired from the Senate at the end of his term in 2019, saying he was out of step with the Republican Party in the era of former President Donald Trump.