Jeff Flake on Tuesday confirmed that he is stepping down from his role as US ambassador to Turkey this September.
“It has been an honour to serve,” he said in a post on X, sharing an article by Axios, which first reported the news.
Mr Flake has held the post since President Joe Biden appointed the moderate Republican in 2021.
He was known for helping the US to convince Turkish President Recep Tayyip Erdogan to approve Sweden's accession into Nato, in response to European concerns over Russian aggression in Ukraine.
By using his Republican connections, he helped the Biden administration to clinch congressional approval to sell F-16 fighter jets to Turkey as part of the Nato expansion hopes.
Mr Flake was particularly active in co-ordinating the American humanitarian aid response to the devastating 2023 earthquakes in Turkey and Syria, which killed more than 60,000 people.
The former Arizona senator may be returning to the US to assist in campaigning against Republican presidential candidate Donald Trump in the pivotal battleground state before the November 5 election.
But Axios reported that Mr Flake's resignation letter seemed to focus more on family priorities than re-entering domestic politics.
