Mr.Trump said he's encouraging her to run for governor when she returns home to Arkansas, where her father once held the governor's seat.

Ms.Sanders is one of Trump's closest and most trusted White House aides and one of the few remaining who worked on his campaign, taking on the job of advocating for and defending a president who had a negative view of the media.

At an unrelated White House event, Trump described Sanders as a "warrior" as he called her to the stage. Sanders, appearing emotional, said serving Trump has been "the honour of a lifetime" and pledged to remain one of his "most outspoken and loyal supporters."

Sanders, who is married and has three young children, later told reporters she wanted to spend more time with her family, but did not rule out running for public office.

Under her roughly two-year tenure as chief spokeswoman for the White House, daily televised briefings led by the press secretary became a relic of the past after Sanders repeatedly sparred with reporters who questioned her about administration policy, the investigation into possible collusion with Russia or other controversies involving the White House.

Sanders has not held a formal briefing since March 11 - more than three months ago - and said she does not regret the decision to scale them back.

Instead, reporters were left to catch her and other administration officials on the White House driveway after their interviews with Fox News Channel and other networks.

The Russia report released by special counsel Robert Mueller she'd 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 characterised the comment as a "slip of the tongue" uttered in the "heat of the moment."

Australian Associated Press