Asserting that US President Donald Trump is an incredibly strong and good leader, the White House has said that questioning his mental fitness is "disgraceful and laughable". "It's disgraceful and laughable. If he was unfit, he probably wouldn't be sitting there and wouldn't have defeated the most qualified group of candidates the Republican Party has ever seen," White House Press Secretary Sarah Sanders told reporters at her daily news conference. Sanders was responding to a question on reports about Trump's mental fitness in view of the series of tweets he made in the new year. The White House press secretary laughed at such a thought mentioned in Michael Wolff's upcoming book "Fire and Fury" that he is mentally unfit to serve as president. Trump, she said, "is an incredibly strong and good\u201d leader.\u00a0 "That's why we've had such a successful 2017 and why we're going to continue to do great things as we move forward in this administration," she said.