Washington (CNN) US Ambassador to Russia Jon Huntsman has submitted his resignation letter to President Donald Trump and plans to move back home to Utah, according to a source familiar with his thinking.

Huntsman's resignation is effective October 3 and there is some speculation that he is planning to run for governor of Utah, a role he previous served in from 2005 to 2009. However, a source close to Huntsman told CNN that decision is still up in the air, saying: "We shall see, it's been a long two years."

The State Department confirmed Huntsman's resignation on Wednesday.

"We thank Ambassador Huntsman for his service and his efforts to advance the Trump Administration's policies in Russia," a State Department spokesperson said in a statement. "Ambassador Huntsman has served as Ambassador to Russia since October 2017, and he will conclude his two-year diplomatic assignment in Moscow in October 2019."

"Ambassador Huntsman previously served as U.S. Ambassador to China (2009-2011) and U.S. Ambassador to Singapore (1992-1993). He was also the Governor of Utah (2005-2009)," the spokesperson's statement continued. "We refer you to Ambassador Huntsman regarding his future plans."