The author of a new biography of Elon Musk has admitted that a controversial detail in an online extract of the book – which suggested that the tech magnate thwarted a Ukrainian drone attack on a Russian naval base in September 2022 – is factually incorrect. The extract from Walter Isaacson’s book, published in the Washington Post on Thursday, originally said that the SpaceX CEO “secretly” told engineers to turn off Starlink coverage within 100km of the Crimean coast to prevent a Ukrainian attack on the area. “As a result, when the Ukrainian drone subs got near the Russian fleet in Sevastopol, they lost connectivity and washed ashore harmlessly,” continued the extract. Musk quickly disputed the story, tweeting that the Starlink regions in question “were not activated” in the first place and that the company “did not deactivate anything”. Instead, there was an “emergency request” from government authorities to activate Starlink to Sevastopol, “the obvious intent being to sink most of the Russian fleet at anchor”, wrote Musk. “If I had agreed to their request, then SpaceX would be explicitly complicit in a major act of war and conflict escalation.” On Friday, Isaacson tweeted a clarification, writing that “the Ukrainians THOUGHT coverage was enabled all the way to Crimea, but it was not. They asked Musk to enable it for their drone sub attack on the Russian fleet. Musk did not enable it, because he thought, probably correctly, that would cause a major war.” On Saturday, Isaacson said that based on conversations with Musk, he “mistakenly” believed that the policy preventing Starlink from being used for an attack on Crimea had been decided on the night of the attempted Ukrainian attack. He added that Musk “now says that the policy had been implemented earlier, but the Ukrainians did not know it, and that night he simply reaffirmed the policy”. In response to Isaacson’s correction, Musk tweeted “Much appreciated, Walter”, adding that the “onus is meaningfully different if I refused to act upon a request from Ukraine vs. made a deliberate change to Starlink to thwart Ukraine”. He also said that Starlink’s terms of service prohibit Starlink being used for offensive military action as it is a “civilian system”. On Thursday, Ukrainian presidential adviser Mykhailo Podolyak said that Musk’s reported actions were “much more than just a mistake” and that civilians being killed “is the price of a cocktail of ignorance and big ego”. The Washington Post extract now features a correction at the top of the article page, and the text has been edited to remove the incorrect claims. Isaacson’s book, released on Tuesday, tells the story of Musk’s life, beginning with his childhood in South Africa.