Secretary of State Rex Tillerson said he has no reason to question President Trump’s “mental fitness."

Tillerson fielded a question from CNN’s Elise Labott concerning Trump’s temperament, which has been discussed after segments were published from the now-released tell-all book, Fire and Fury: Inside the Trump White House, and largely paints Trump in a negative light.

"I've never questioned his mental fitness," Tillerson said in the interview, released Friday. "I have no reason to question his mental fitness."

The question comes after Politico reported that more than a dozen lawmakers concerned with Trump's mental health discussed the president with a Yale University psychiatrist.

During the CNN interview Tillerson also said, despite what rumors and reports have suggested, he plans to stay on as secretary of state through the end of 2018.