Senators look at a placard presented as evidence of Russian social media manipulation, during a Senate Intelligence Committee hearing to answer questions related to Russian use of social media to influence U.S. elections, on Capitol Hill in Washington, November 1, 2017.

The tweet that opened a story in the Washington Post on Feb. 11, 2016 seemed innocuous: It was an attempt to illustrate Syrian territory occupied by clashing government and ISIS forces.

Problem is, the account behind that tweet — @WarfareWW — was one of 2,752 Twitter trolls identified this week as tied to the Russian government and suspended for spreading disinformation.

U.S. lawmakers are probing the extent of the Kremlin's campaign to disrupt last year's presidential election and have focused their latest efforts on tech platforms like Twitter.

But new data show that many news publications — from established outfits like the Post, the Miami Herald (owned by McClatchy), Buzzfeed, CBS and even Vox, to controversial alt-right hubs like InfoWars — were duped into citing some of these nefarious tweets in their coverage, perhaps unwittingly amplifying the reach of Russian propaganda.

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The Post was one of the most prominent news organizations to include the bogus, misleading tweets in their stories. On at least eight occasions since early 2016, the paper cited Twitter accounts that since have been pegged as Kremlin-sponsored trolls, according to an analysis by Recode with the aid of Meltwater, a media-intelligence firm.

To perform the study, Meltwater analyzed online news sources in the U.S. — from major sites and services like the Associated Press to community pages like Patch — between Jan. 1, 2016, and Sept. 30, 2017. It specifically sought to identify accounts that have been linked to the Internet Research Agency, the Kremlin's online troll army.

The firm recorded those pages at the time of their publication. Some of the links are now defunct. And it's impossible to know if the tweets were written by Russian trolls at the time they ended up in stories at the Post or elsewhere, or if the accounts were genuine for a time — then later hijacked by Russia's IRA — before being shuttered.

In many cases, though, the tweets were presented as authentic community voices on an issue — the digital man-on-the-street interview, so to speak. And some still live intact online.

Brought to the Post's attention, the newspaper on Thursday night updated at least one of its stories — its piece on Syria. It replaced the troll tweet in question with a note flagging that it had been tied to the Russian government.

And the Post's executive editor, Marty Baron, told Recode on Friday that his newspaper would rethink the way it approaches tweets in stories.

"Obviously, we regret linking to any Twitter account that we have learned is illegitimate," he said in a statement. "We'll seek to rectify any stories that contain such links, and we'll now assess our policy regarding the publication of links to Twitter accounts."

Twitter declined to comment.

Other affected stories include a 2016 piece about Sen. Ted Cruz. The Post sought to parse online criticism of the lawmaker, after he accused Donald Trump during the GOP presidential primary of harboring "New York values."

Cruz's comment suggested Trump secretly endorsed NYC-style liberalism, and the paper quoted a number of tweets, including one from the account @jenn_abrams, which appeared to describe their outrage at Cruz's comment. That account is a troll. Some time after its inclusion in the Post story, it was suspended on Twitter.

In a March 2017 piece, meanwhile, the Post cited a tweet from @SouthLoneStar as an example of racist, alt-right trolling online. That's certainly a problem on Twitter, no stranger to such abuse — but the account is the work of Russian agents that are unidentified in the story.

The same account cropped up in a number of other stories, including a post by The Hill in February 2017. There, the tweet encouraged readers to buy Ivanka Trump's line of jewelry.

To that end, the extent of the Kremlin's disinformation efforts — and its leap from the depths of social media to the webpages of the country's most well-read publications — raised alarms with top Democrats investigating Russia's disinformation campaign.

"The fact that these fake accounts were able to fool legitimate news outlets into repeating their messages shows just how difficult it is for even well-informed Americans to identify Russian-produced propaganda on social media," said Sen. Mark Warner, the top Democrat on his chamber's intel panel, in a statement to Recode.

"The extent to which legitimate, mainstream news outlets picked up and amplified Russian misinformation is an illustration of its pernicious reach," he said.

The reach is so vast that other respected news brands did not escape unscathed, either.

Consider a story by the news service McClatchy on Dec. 1 about "The Daily Show" host Trevor Noah, who had sparred with conservative talking head Tomi Lahren about Black Lives Matter. The recap, which appeared on a number of McClatchy-owned sites like the Miami Herald, included a tweet from the account @BlackToLive.

Twitter has since identified that handle as tied to Russia's official troll farm, the IRA. In many cases, including the @BlackToLive account, such trolls specifically sought to pose as activists or other organizations on both sides of debates about touchy subjects like immigration, gun control, gay rights and race.

Another tweet from @BlackToLive appeared on CBS Sports in a story this August about Colin Kaepernick, the former NFL quarterback who has been protesting racial inequality. Months after that story ran, U.S. lawmakers began to realize that the account and other, similar Russian trolls had been trying to stoke tensions around pro football's anthem demonstrations.

"Throughout the 2016 election and since, it's clear that Russian online efforts have some very real impact in shaping news coverage, as we saw recently with the NFL protests," Rep. Adam Schiff, the top Democrat on the House Intelligence Committee, told Recode this week. "We may never know the full effect of the Russians' pernicious efforts online, but we must continue to expose these tactics wherever possible and inoculate ourselves against future interference."

Even Vox.com, a sister site of Recode, was not immune: A tweet from a Russian troll appeared in an October 2016 piece about Emmett Till. (Vox Media owns Vox and Recode.)

Nor was Buzzfeed. One story from November 2016 featured a tweet about "an illegal alien trying to vote" from a since-suspended, Russian-linked account. The piece, however, called out the substance of that tweet as false. Another, from around the 2016 presidential election, included a tweet from the Kremlin-supported @BlackToLive account.

And in many cases, conservative-leaning or alt-right sites peddled considerable Russian disinformation. Kremlin troll accounts appeared repeatedly over two years on Infowars, the infamous, conspiracy-minded site helmed by Alex Jones.

It also surfaced at The Daily Caller. This August, the publication sought to raise hell around Charlie Hebdo, a satirical publication in France. The piece accused the French newspaper of making light of those affected earlier this year by Tropical Storm Harvey. ("God Exists! He Drowned All the Neo-Nazis of Texas," read the headline in question.)

To make its point, The Daily Caller pointed to negative reactions from folks including Twitter user @thefoundingson. That account has been identified as a Russian government troll.

On certain days, Russia's disinformation efforts appeared to have exceptional reach. That included Dec. 1, 2016, when Russia-backed Twitter accounts were cited in 164 stories, according to Meltwater data. A key driver appears to have been Patch, which is controlled by investment firm Hale Global with minority ownership by Verizon's Oath. The subject: Cereal-maker Kellogg's had ceased advertising on the alt-right site Breitbart.

The widely duplicated piece included tweets from @TEN_GOP. For months, that account sought to impersonate the official Republican Party of Tennessee, until Twitter shut it down in August 2017. Its widespread disinformation efforts recently have been chronicled by a number of publications, including HuffPost.

A similarly named account — @10_gop — surfaced in a story about Hurricane Irma that ran in the Independent Journal Review this September, and another about immigration surfaced that same month in The Blaze. Even President Trump once retweeted the Russian troll account.

The second-biggest day for these Russian-tied Twitter trolls came on Aug. 17, 2016, Meltwater data show, with 140 mentions in news stories across the web. Some of those stories focused on Russia bombing Syria, and they cited tweets from @WarfareWW, the same handle that had appeared in the Post months earlier. Perhaps its interest in Syria is no accident: Russia had been an ardent supporter of its leader, Bashar al-Assad.

Since then, though, the handle has been shuttered, and some of the stories citing it — which also appeared on sites like the Idaho Press-Tribune and the Missourian — have disappeared online.

To lawmakers, at least, these and other tweets still illustrate the sheer pervasiveness of Russia's efforts — and the reasons why tech companies and others must act swiftly to guard against future attempts to meddle in U.S. politics.

"Those who have tried to downplay the potential influence these fake accounts had on American voters ought to reflect upon the many ways in which these messages were echoed and intensified across several platforms," Sen. Warner told Recode.

—By Tony Romm and Rani Molla, Recode.net.

CNBC's parent NBCUniversal is an investor in Recode's parent Vox, and the companies have a content-sharing arrangement.