In late September, Zuckerberg used his Facebook Live feature to outline steps the company is taking to make its platform less vulnerable to political issues like selling ads to foreign operatives looking to influence US elections.
As part of a broad internal inquiry - which also spans sites like YouTube - Google also identified about $53,000 in ads that are connected to Russian Federation, through markers like a local billing address, but may not be explicitly tied to the Kremlin, the source said.
Facebook has said the Russian company had placed 3,000 ads on its network at a cost of about $100,000. Facebook has said those ads reached just 10 million of the 210 million United States users that log onto the service each month.
The alleged investigation goes against Google's previous attempts to play down the scale of Russian interference on its systems.
The report said the company discovered the Russian presence by siphoning data from Twitter. There were also posts created to stoke cultural tensions in the country, such as anti-immigrant material, according to the Washington Post.
All three firms are expected to appear on November 1 in an open Senate Intelligence Committee hearing on the rising evidence that they were covertly manipulated in a campaign to help Donald Trump win the presidency. Jigsaw has been doing research for 18 months on fake news and misinformation campaigns and it is using some of those findings in the investigation into Russian election meddling, the person said.
The 2016 presidential election marked the first time that Google allowed targeting by political leanings and it allowed two categories - left-leaning and right-leaning. Later, Twitter also found that 200 accounts on its platforms were in some way linked to the profiles that Facebook flagged previously.
Questioned by AFP, a spokesman for Google merely to indicate that the group "had a series of very strict rules in terms of sponsored content, including limits on the targeting of political content sponsored and the prohibition to target content according to the race and the religion". Social media companies Facebook and Twitter have already agreed to testify.