The American ambassador to Russia, Jon Huntsman, will resign and return to his home state of Utah, NBC News confirmed Tuesday.
The former Utah governor sent a letter to the White House on Tuesday morning saying he would step down. His resignation is effective Oct. 3, according to the letter obtained by NBC News.
The White House and State Department did not immediately respond to CNBC's request to comment. The Salt Lake Tribune first reported the news Tuesday.
Huntsman, a 59-year-old Republican who was Utah's governor from 2005 to 2009, could run for the office again in 2020, according to the newspaper. He left office in 2009 to become President Barack Obama's ambassador to China and later mounted an unsuccessful bid for the GOP presidential nomination in 2012.
Trump has faced relentless criticism for U.S. relations with Russia. He has repeatedly praised Russian President Vladimir Putin and said he believes the strongman's denials that Moscow did not interfere in Trump's 2016 presidential election victory.
Trump has insisted that he wants to have a good relationship with Russia, which can be a formidable geopolitical foe for the U.S.
In Huntsman's resignation letter, he wrote that "we must continue to hold Russia accountable when its behavior threatens us and our allies." He added that "through our diplomacy, we have worked to stabilize years of acrimony and incertitude with the hope of a better relationship."
If he decides to run for governor, Huntsman would face Lt. Gov. Spencer Cox in the Republican primary.
— CNBC's Brian Schwartz contributed to this report