WASHINGTON, D.C. - Bill Clinton thought U.S. President Barack Obama was "incompetent" and "an amateur," and wanted his wife to challenge him for this election's Democratic nomination, according to a new book.

Edward Klein's unauthorized bio of Obama, The Amateur, recounts a gathering in August 2011 in the Clinton's Chappaqua, N.Y., home in which the former president railed against Obama's handling of the economy and pressed Secretary of State Hillary Clinton to quit her job.

"The economy's a mess, it's dead flat. America has lost its triple-A rating ... You know better than Obama does," Bill told her, according to book excerpts. "The country needs you!"

"Barack Obama," he allegedly added, "is an amateur," and "doesn't know how to be president," and is "incompetent."

The Clintons and the White House flatly denied the claims, according to the New York Post, which first wrote about the explosive revelations Thursday.

Bill Clinton's spokesman, Matt McKenna, said the claims in the book are "totally and completely false" and accused Klein -- a one-time editor of the New York Times Magazine and Newsweek -- of being "a known liar."

White House spokesman Eric Schultz even suggested Klein was making things up to sell books.

"Nobody in their right mind would believe the nonsense in this one, especially since both Secretary Clinton and President Clinton have been loyal and supportive of the president at every turn."

Hillary Clinton reportedly also challenged the accuracy of Klein's early book on her, Truth About Hillary.

According to the new book, Hillary Clinton brushed off her husband's suggestion she quit and run against Obama, saying she wanted to leave a legacy as a good secretary of state, and that she was loyal to Obama.

Also, she said, there was time for her to run in 2016.