Donald Trump on Saturday called Michael Wolff, the writer of a bestselling book about his White House, “a mentally deranged author” who “knowingly writes false information”.

“So much Fake News is being reported,” the president wrote on Twitter. “They don’t even try to get it right, or correct it when they are wrong. They promote the Fake Book of a mentally deranged author, who knowingly writes false information. The Mainstream Media is crazed that WE won the election!”

Wolff’s book, Fire and Fury: Inside the Trump White House, exploded into the public consciousness last week. The Guardian was first to publish excerpts, concerning former Trump adviser Steve Bannon’s view of a Trump Tower meeting between aides and a group of Russians in the midst of the presidential campaign.

Embarrassing details of White House life were published by other media outlets, leading to a renewed focus on Trump’s mental state and capacity for his job.

Trump sought to prevent publisher Henry Holt & Co from releasing the book, only for his legal threat to prompt publication to be brought forward. The book shot to the top of bestseller lists worldwide.

Trump has attacked Wolff and his work before. On Saturday, the president did not immediately specify which information in Wolff’s book he claimed to be false. The White House has said the book is “fiction” and questioned Wolff’s bona fides and access to the president himself.

Wolff has said he conducted more than 200 interviews and stands by all his sourcing and reporting. News outlets have pointed to inconsistencies in Fire and Fury and in past work.

Bannon, a key source for Wolff, speculates in the book that Trump himself may have met the lawyer and other Russians who met key aides at Trump Tower in June 2016 after suggesting they had incriminating material on Hillary Clinton.

Bannon issued a statement last weekend in which he said his comments about the meeting being “treasonous”, “unpatriotic” and “bad shit” had not been aimed at Trump’s son, Donald Trump Jr, but at then campaign manager Paul Manafort, one of four Trump aides to have been indicted under special counsel Robert Mueller’s investigation into Russian election meddling.

He did not mention Trump’s son in law, Jared Kushner, who also attended the meeting. Nor did Bannon retract his view of the character or advisibility of the gathering.

Wolff’s book also contains details of the drafting of a misleading statement about the meeting, at the direction of Trump and onboard Air Force One.

Bannon has been disowned by the president and key Republican donors. He lost his job at the far-right Breitbart News website.

The president’s tweet on Saturday followed a relatively quiet day, in which the White House said he had been briefed in depth about issues relating to China.