The Washington Post reported the White House may be looking to replace Secretary of Defense James Mattis, who many have seen as an experienced advisor who has moderated some of the president's demands.

The report comes in the heels of controversy after a book by Bob Woodward claimed Mattis has made controversial statements about the president.

Mattis has vehemently denied making or hearing the statements, and Trump insists he is not looking to replace the defense secretary.

Secretary of Defense Jim Mattis may be on his way out of Washington soon, according to the Washington Post.

President Donald Trump, according to unnamed sources within the White House, is eyeing replacements for the widely respected retired general in the wake of controversial statements attributed to Mattis in Bob Woodward's new book, "Fear: Trump in the White House."

In one phone call as reported in "Fear," Trump told Mattis to assassinate Syrian President Bashar al-Assad and Mattis seemed to agree to his demand, only to tell an aide afterwards, "We're not going to do any of that. We're going to be much more measured."

Although it is uncertain whether Trump will replace Mattis, who has vehemently denied making or hearing any of the statements reported in "Fear," the Post has published what appears to be a shortlist of potential successors.

On top of the list is retired Army Gen. Jack Keane, who once served as vice chief of staff of the Army. Keane, who retired in 2003, would not require a Congressional waiver to serve as he has been out of military service for longer than seven years. Keane was one of Trump's earliest front-runners for the position; declining for personal reasons, he told NPR in November 2016 that he advised Trump to select Mattis or retired Gen. David Petraeus instead.

Also on the list is Sen. Tom Cotton (R-Ark.), who spent five years as an Army officer and whose service includes combat tours in Afghanistan and Iraq. Cotton currently serves on the Senate Armed Services Committee. Sen. Lindsey Graham (R-S.C.) a retired Air Force colonel who also serves on the SASC, is also reportedly being considered, although he has previously stated he would not accept a cabinet position. The report also mentions that Trump may not want to risk pulling either senator from their positions until after the November elections.

Former Treasury Department official David McCormick has also been mentioned, as well as former senator Jim Talent. McCormick was considered for positions in both the Defense and Treasury departments during the transition, and Talent was considered for defense secretary in late 2016, according to the Post.

According to a Reuters report Wednesday, Trump says regardless of the claims made in Woodward's book — which both the President and Mattis have called "fiction" — he is "very happy" with Mattis, and plans to keep the retired Marine Corps general in his position.

Correction: An earlier version of this article erroneously stated the state that Sen. Cotton represents. He represents Arkansas.