Russian President Vladimir Putin casts his ballot at a polling station during the municipal elections in Moscow on September 10. Yuri Kadobnov/Pool/Reuters A fuller picture of Russia's use of social media to influence the 2016 US election has begun to emerge, weeks after Facebook announced that "inauthentic" accounts most likely operating out of Russia had purchased $100,000 worth of political ads between 2015 and 2016.

A steady stream of leaks most likely coming from Capitol Hill — Facebook said late last week that it would turn over the ads to Congress — have indicated the ads and the accounts that bought them were focused primarily on exploiting divisions over issues like race and immigration.

And as Business Insider has previously reported, the accounts' activity did not stop at posting controversial memes and hashtags — many organized events, rallies, and protests, some of which galvanized dozens of people.

Facebook was not oblivious to the Russians' presence on the platform — The Washington Post reported this week that the company contacted the FBI last June when it noticed that members of a hacking group connected to Russia's military intelligence unit, the GRU, had begun creating fake accounts to amplify stolen emails.

The US intelligence community concluded in January that the social-media operation was part of a larger influence campaign by Russia — and that assessment, according to former intelligence chief James Clapper, "did serve to cast doubt on the legitimacy" of the election outcome.

Here's what we know so far about how the Russians used one of the biggest tech companies in the world to energize and influence American voters:

Facebook CEO Mark Zuckerberg has been criticized by those who say he shrugged off warnings about the fake-news epidemic on the platform. The Post reported that President Barack Obama asked him just after the election to take it seriously, but that Zuckerberg replied that the company's power to control the spread of information was limited.

Under mounting pressure, however, Zuckerberg announced last week that Facebook had developed a nine-point plan to examine the Russian influence campaign and prevent similar efforts in the future.

Among the changes: Facebook says it will start disclosing which pages paid for political ads, and it plans to partner with election commissions and cyber-threat specialists to mitigate misuse of its platform.

"I care deeply about the democratic process and protecting its integrity," Zuckerberg said during a live broadcast on his Facebook page. "I don't want anyone to use our tools to undermine democracy."

Robert Mueller, the special counsel leading the FBI's investigation into Russia's election interference, recently obtained a search warrant for the Russia-linked accounts and the ads they purchased, according to The Wall Street Journal and CNN.

He is also investigating whether the Trump campaign colluded with Moscow. Congressional investigators like Rep. Adam Schiff, the ranking Democrat on the House Intelligence Committee, are looking into whether this may have manifested through the data operation run by Trump's son-in-law, Jared Kushner, who's now a senior White House adviser.