President Donald Trump denied allegations in a coming book by journalist Bob Woodward that he directed Defense Secretary James Mattis to “kill” Syrian President Bashar al-Assad.

“That was never even contemplated, nor would it be contemplated,” the president said Wednesday.

Trump also delivered a new warning to Assad, saying “the world is watching, and the United States is watching, very closely” at whether the Syrian strongman uses chemical weapons in Idlib province, the final remaining area controlled by opposition forces in the country.

“The book is total fiction,” Trump said dismissively of Woodward’s “Fear: Trump in the White House,” adding his view that Woodward’s books about presidents George W. Bush and Barack Obama also were built on untruths.

Trump, sitting alongside his Kuwaiti counterpart in the Oval Office, told reporters Woodward’s coming book “was put out to interfere in, my opinion, with the Kavanaugh hearings.”

“So many people who have been written about said that I never said that,” he said, referring to Mattis and White House chief of staff John Kelly issuing statements taking umbrage with Woodward’s reporting, which was based on hundreds of hours of interviews with current and former Trump aides.

In one account, the Watergate sleuth, citing multiple sources, contends Kelly once told colleagues the president is “unhinged.”

“He’s an idiot. It’s pointless to try to convince him of anything. He’s gone off the rails. We’re in Crazytown,” Woodward alleges Kelly said to a small group of staffers. “I don’t even know why any of us are here. This is the worst job I’ve ever had.”

The coming book also includes Trump, as he has done on Twitter in recent days, lashing out privately at Attorney General Jeff Sessions, calling him a “traitor” for choosing to recuse himself from Special Counsel Robert Mueller’s Russia election meddling investigation. But, according to Woodward, Trump was not finished.

“This guy is mentally retarded. He’s this dumb Southerner,” he said of the former GOP senator. “He couldn’t even be a one-person country lawyer down in Alabama.”

The White House called many of the stories in the book “fabricated,” but neither the president nor his aides have yet refuted the references to Sessions.