"Oh f---, how did we miss this?" Facebook CEO Mark Zuckerberg asked, looking around at the somber faces of his top executives, the N.Y. Times' Sheera Frenkel and Cecilia Kang write in their book, "An Ugly Truth: Inside Facebook’s Battle for Domination," out Tuesday.

In an excerpt provided first to Axios, the authors write that the executives met Dec. 9, 2016, for a briefing on what Facebook's security team knew about Russian meddling on the platform during the election won by Donald Trump.

The security team, it turns out, had first spotted Russian activity on the platform in March 2016. But Zuckerberg and COO Sheryl Sandberg were just being told about it nine months later.

• The eight-page handout for the meeting — written by Alex Stamos, then Facebook's chief security officer — "acknowledged that Facebook was sitting on a trove of information proving that a foreign government had tried to meddle in the U.S. election."

Frenkel and Kang, in a chapter called "Company Over Country," write that "no one else spoke as Zuckerberg and Sandberg drilled their chief security officer":

What happened: The security team "had uncovered information that no one, including the U.S. government, had previously known," the authors write.

• "Stamos felt that he had been trying to sound the alarm on Russia for months."
• Stamos said: "It was well within my remit to investigate foreign activity within the platform. And we had appropriately briefed the people in our reporting chain ... It became clear after that that it wasn’t enough."

At the meeting, "Stamos gave a somber assessment of where they stood, admitting that no one at the company knew the full extent of the Russian election interference," we learn from "An Ugly Truth."

• "Zuckerberg demanded that the executives get him answers, so they promised to devote their top engineering talent and resources to investigate what Russia had done on the platform."

Facebook spokesperson Dani Lever said in a previous statement to Axios about the book:

• "There’s no silver bullet to fighting misinformation and disinformation, which is why we take a comprehensive approach which includes removing fake accounts and coordinated networks, connecting people to reliable information, and running an historic, independent fact-checking program." 

Go deeper: Read a N.Y. Times adaptation (subscription).