Social media network Facebook said on Wednesday it had found that an operation probably run from Russia spent $100,000 on thousands of US ads promoting divisive social and political messages in a two-year-period through May.

Facebook said 3,000 ads and 470 “inauthentic” accounts and pages spread polarizing views on topics including immigration, race and gay rights into what investigators believe was a targeted effort by Russians to influence US politics during the 2016 US presidential campaign, this time through social media.

Another $50,000 was spent on 2,200 “potentially politically related” ads, likely by Russians, Facebook said.

Facebook announced the findings in a blog post by its chief security officer, Alex Stamos, and said that it was cooperating with federal inquiries into influence operations during the election.

Facebook briefed members of both the Senate and House of Representatives intelligence committees on Wednesday about the suspected Russia advertising, according to a congressional source familiar with the matter. Both committees are conducting probes into alleged Russian interference in the US election, including potential collusion between the campaign of President Donald Trump and Moscow.

Facebook also gave its findings to Robert Mueller, the special counsel in charge of investigating alleged Russian interference in the election, a source familiar with the matter said. The company produced copies of advertisements as well as data about the buyers, the source told Reuters.

The dollar amount of ad spending identified by Facebook is an infinitesimal amount compared to the total amount of advertising spending during the election. According to ad tracker Borrell Associates, more than $1.4 billion was spent during the 2016 election cycle on digital advertising alone. That figure includes spending on national, state and local elections.