White House press secretary Sarah Sanders, whose tenure was marked by a breakdown in regular press briefings and questions about the administration's credibility, as well as her own, will leave her post at the end of the month, President Donald Trump announced Thursday.

Trump, calling Sanders forward at an unrelated event in the East Room, called her "a warrior" and said he was encouraging her to run for governor as she returns home to Arkansas. She is one of Trump's closest and most trusted White House aides and one of the few remaining on staff who worked on his campaign.

Trump announced her impending departure via tweet just before she accompanied him to a White House event on prison reform: "After 3 1/2 years, our wonderful Sarah Huckabee Sanders will be leaving the White House at the end of the month and going home to the Great State of Arkansas."

He added that "she would be fantastic" as Arkansas governor.

Sanders said serving as press secretary had been "the honor of a lifetime." She pledged to remain "one of the most outspoken and loyal supporters of the president."

Under Sanders' tenure, regular White House press briefings became a relic of the past. She has not held a formal briefing since March 11. Reporters often catch her on the White House driveway after she is interviewed by Fox News Channel or other TV news outlets.

Her credibility has also come under question.

Special counsel Robert Mueller's Russia report revealed that Sanders admitted to investigators that she had made an unfounded claim about "countless" FBI agents reaching out to express support for Trump's decision to fire FBI Director James Comey in May 2017.

Sanders succeeded Sean Spicer, Trump's first press secretary, in mid-2017.