Ferguson and Baltimore had gained widespread attention for the large and violent protests over police shootings of black men. The decision to target the ad in those two cities offers the first look at how accounts linked to the Russian government-affiliated troll farm known as the Internet Research Agency used geographically targeted advertising to sow political chaos in the United States, the sources said.

Facebook has previously said that roughly one-quarter of the 3,000 ads bought by the agency were geographically targeted, but it has not revealed any specific locations. Facebook has also not revealed which demographic groups and interest groups were targeted by the ads.

The Black Lives Matter ad appeared on Facebook at some point in late 2015 or early 2016, the sources said. The sources said it appears the ad was meant to appear both as supporting Black Lives Matter but also could be seen as portraying the group as threatening to some residents of Baltimore and Ferguson.

Exclusive: Russians bought Black Lives Matter ad on Facebook targeting people in Baltimore and Ferguson https://t.co/erapRyhA1O pic.twitter.com/1INgFT35JZ

— The Situation Room (@CNNSitRoom) September 27, 2017

New descriptions of the Russian-bought ads shared with CNN suggest that the apparent goal of the Russian buyers was to amplify political discord and fuel an atmosphere of incivility and chaos, though not necessarily to promote one candidate or cause over another. Facebook’s review of Russian efforts on its platform focused on a timeframe from June 2015 to May 2017.

Sen. Richard Blumenthal says he has seen some of the Russian-bought Facebook ads, describing them as “shocking” https://t.co/GIWsdv3A2C

— The Situation Room (@CNNSitRoom) September 27, 2017

These ranged from posts promoting Black Lives Matter to posts promoting gun rights and the Second Amendment to posts warning about what they said was the threat undocumented immigrants posed to American democracy. Beyond the election, Russians have sought to raise questions about western democracies.

“This is consistent with the overall goal of creating discord inside the body politic here in the United States, and really across the West,” Steve Hall, the former CIA officer and CNN National Security Analyst, said. “It shows they the level of sophistication of their targeting. They are able to sow discord in a very granular nature, target certain communities and link them up with certain issues.”