Russian operatives targeted users on Facebook Inc. FB -0.90% by race, religion and interests such as gun ownership, the Confederate flag and Ivanka Trump’s jewelry line, according to advertising data released by lawmakers Wednesday as part of congressional investigations into Russian manipulation on social media around the U.S. election.

The ads targeted groups on opposite sides of an issue, a move that lawmakers said was designed to amplify social divisions. One of the Russia-backed pages, “Back the Badge,” for example, ran an ad in October 2016 meant to reach the wives of police officers, sheriffs and pages memorializing killed officers that was seen more than 1.3 million times. “Woke Blacks,” on the other hand, promoted its page among people who are interested in “African-American culture” and the civil-rights movement. That ad was seen more than 750,000 times. Both pages were created by Russians tied to the Kremlin-linked Internet Research Agency, which paid for the ads in rubles.

Lawmakers also released the Twitter Inc. account names for 2,752 accounts linked to the Internet Research Agency. Many of the handles appeared to impersonate famous politicians, political parties and news agencies, in an apparent attempt to seem credible, such as @_GeorgeSchultz_, @tpartynews, @NewYorkDem and @TheTimesOfLondn. At least one of the accounts was created as early as 2009 and another was tweeting as recently as mid-October, according to data analyzed by The Wall Street Journal. Some accounts with more than 10,000 followers were created in late 2015 as the presidential primaries were in full swing.

Social media “in many ways seem purpose-built for Russian disinformation techniques,” Sen. Mark Warner (D., Va.) said during a Senate Intelligence Committee hearing on Wednesday attended by executives from Facebook, Twitter and Alphabet Inc.’s Google to probe Russian manipulation. “Russian actions are further exposing the dark underbelly of the ecosystem you have created.”

Russia has denied any interference in the U.S. election.

The new data, released by members of the House Intelligence Committee during an afternoon hearing, show the sophistication of the Russian effort to hit precise groups of people to amplify specific, simmering tensions within the U.S. Facebook, Twitter and Google have said in congressional hearings this week that the ads and other content by Russian-linked accounts made up just a sliver of election-related information on their sites. But the ads demonstrate how the Russian effort spread far beyond political campaigns and across issues as wide-ranging as immigration, police brutality and religion, and served to recruit new followers to their pages and encourage them to attend events.

Lawmakers expressed frustration with the tech companies during the hearings. Sen. Dianne Feinstein (D., Calif.) criticized the companies for not having a handle on the misuse of their platforms, while Sen. Angus King (I., Maine) said he was disappointed the tech companies didn’t send their chief executives.

Based on the information that's now coming out of congressional committees, Russian goals to interfere in the 2016 election were very broad. WSJ's Gerald F. Seib explains just how sophisticated the Russian efforts were using social media. Photo: AP

“We’re serious about preventing abuse on our platforms,” Facebook Chief Executive Mark Zuckerberg said in a statement as part of Facebook’s quarterly earnings Wednesday afternoon. “Protecting our community is more important than maximizing our profits.”

Russian-created posts reached an estimated 146 million people on Facebook, including 20 million people on Instagram, Facebook said Wednesday. Twitter says its users saw automated, election-related tweets from accounts tied to Russia approximately 288 million times over slightly more than 10 weeks between Sept. 1 and Nov. 15, 2016.

The Russian propaganda campaign achieved such scale at a low cost by tapping hot-button subjects that tend to generate a lot of engagement on Facebook. The company’s ad auction system favors ads that grab users’ attention and prompts them to click or otherwise interact with the ad.

Facebook Messenger CEO David Marcus talks about Russia's allegedly malicious use of the app in the 2016 presidential election. He speaks with WSJ's Christina Passariello at the WSJ D.Live conference in Laguna Beach, Calif.

The Russian actor behind the “Back the Badge” page spent just 0.14 cent, for example, for each user its ad was intended to reach. Facebook General Counsel Colin Stretch said during the hearing the Russian-backed Internet Research Agency spent $46,000 on ads ahead of the 2016 U.S. presidential election, compared with a combined $81 million in spending from Hillary Clinton and Donald Trump’s campaigns prior to Election Day. Twitter has identified $235,784 in advertising spent by Russian-linked accounts that was targeted at U.S.-based users in 2016.

The Russian social-media campaign was successful because “they understood that the algorithms that you use tend to accentuate content that is either fear based or anger based,” said Rep. Adam Schiff of California. “That helps it pick up an audience and go viral and be amplified.”

Other ads appeared on Instagram, Facebook’s photo-sharing service. Facebook has only recently started to acknowledge the scale of Russian manipulation on Instagram. “Killary Clinton will never understand what it feels like to lose the person you love for the sake of your country,” said an ad from an Instagram account called “american.veterans.” Russian actors paid 3,083.95 rubles, or about $53 at current exchange rates, to target veterans. The ad was viewed 17,654 times.

Facebook in September identified 470 accounts linked to the Internet Research Agency, which operated 120 pages. It disclosed at the time that the accounts bought 3,000 ads during a two-year period, but didn’t make them public. Some lawmakers vowed to release them in order to make Americans more aware of the Russian manipulation.

Some ads promoted events, often on opposite ends of the ideological spectrum. For example, in May 2016 the “United Muslims of America” page coordinated a rally to support a recently opened Islamic center in Houston. That same day, another Russia-backed Facebook page, “Heart of Texas,” had planned a protest of the center.

The two rallies drew dozens of attendees and attracted local news coverage. The cost of promoting these events on Facebook was $200, said Sen. Richard Burr (R., N.C.) during a hearing Wednesday morning.

In July 2015, “Black Matters” bought a news feed ad to promote its Facebook page, which had nearly 224,000 likes at that point. The page targeted the ad to users located within about 12.5 miles of three cities with large black populations: Atlanta, Ferguson, Mo., and St. Louis.

The ad, backed by a Facebook page called “Williams&Kalvin,” urged Facebook users to subscribe to its channel on YouTube, a unit of Google. Russian actors paid 1,126.07 rubles, or about $19, for the ad, which was viewed 15,000 times.

Twitter initially identified 201 accounts on its site that were related to the 470 Russia-backed accounts Facebook found on its site. This week, Twitter revealed the number of Internet Research Agency-linked accounts was more than 10 times greater than its first sweep.

Some of the Russian Twitter accounts were active until very recently. One, which used the name “Chelsey Jones” and the handle @cheelsyJoTRs, on October 14 tweeted: “BUSTED! Two Obama ’Dreamers’ Arrested For Smuggling in Illegals!” The account had #MAGA in its profile description. At least one account was tweeting in Russian on Oct. 22.

At least 20 of the accounts had amassed more than 10,000 followers. Among the largest was @TEN_GOP, which pretended to be the “Unofficial Twitter of Tennessee Republicans” and recently had more than 144,000 followers before it was suspended by Twitter.

—Douglas MacMillan, Byron Tau, Mark Maremont

and Rob Barry

contributed to this article.

Corrections & Amplifications

The Internet Research Agency operated an account on Twitter called @TheTimesOfLondn. An earlier version of this article incorrectly said the group operated the Twitter account @TheTimesOfLondon.