Backers of President Donald Trump are sharing more “junk” political news – ideologically extreme, conspiratorial, sensationalist and phony information – over Twitter and Facebook than all other groups combined, significantly magnifying the polarization in the American electorate, according to an analysis by British researchers.

Rather than obtaining news over social media from mainstream outlets, these Americans shared posts from 92 Twitter accounts of fringe groups such as "100PercentFEDUp," "Beforeitsnews," "TheAngryAmericans" and "WeArethenewmedia" during the three months before Trump’s first State of the Union address, the Oxford University researchers reported.

The study, which culled data from hundreds of thousands of social media accounts, found similar patterns among Facebook users.

Although the “junk” news sites considered in the analysis included those on both the left and right, lead researcher Philip Howard said the findings suggest "that most of the junk news that people share over social media ends up with Trump’s fans, the far right. They’re playing with different facts, and they think they have the inside scoop on conspiracies."

As a result, he said in a phone interview, it appears that "a small chunk of the population isn’t able to talk politics or share ideas in a sensible way with the rest of the population."

“That’s a problem for democracy," Howard said. "In an ideal world, everybody would get at least a few of the same news stories, There’d be some shared facts and some shared understanding of the problems” facing the country.

Oxford’s Internet Institute has been at the forefront in studying the impact of the expanding use of social media on politics and democracy in more than two dozen Western countries. The Oxford researchers previously published analyses of the reach of "junk news" during the 2016 U.S. election campaign, especially in Michigan, a presidential swing state, and among military veterans.

Trump’s combative style and daily tweets have complicated matters further. Since his presidential campaign, he has repeatedly accused many mainstream U.S. news outlets, including The New York Times, the Washington Post and CNN, of publishing and broadcasting “fake news” critical of him, his family and his administration.

The Oxford study cited “increasing evidence of a rise in polarization in the U.S. news landscape in response to the 2016 election.”

“Trust in news is strikingly divided across ideological lines, and an ecosystem of alternative news is flourishing, fueled by extremist, sensationalist, conspiratorial, masked commentary, fake news and other forms of junk news.”

The researchers gathered the names of hundreds of thousands of public Facebook and Twitter accounts over an 18-month period and, using a set of criteria defining junk news, winnowed them to a list of “obvious” sites, Howard said. “These are the sites that anybody in their right mind would qualify as extremist, sensationalist, conspiratorial.”

“They use swear words in the headlines … or all capital letters. It’s stuff you might call commentary masking as news, if you were being generous.”

Among those on Oxford’s list are Breitbart News and InfoWars, two popular far-right sites that have been especially sympathetic to Trump and his administration. McClatchy reported in March that federal investigators were examining whether those or other ultra-right sites collaborated in any way with Russia’s broad cyber operation aimed at disrupting the 2016 U.S. presidential election and ultimately, according to top U.S. intelligence agencies, sought to defeat Hillary Clinton and elect Trump.

Under pressure from investigators for the House and Senate Intelligence Committees, Facebook and Twitter since have conducted internal investigations and found that Russian operatives created tens of thousands of automated election-related accounts on Twitter and hundreds of fake accounts on Facebook.

There has been no indication that either Breitbart or InfoWars has since been implicated in investigations by Justice Department Special Counsel Robert Mueller and the intelligence committees, which also are investigating whether Trump’s campaign colluded with Russian operatives.

In addition, the researchers’ list of “junk” sites includes the conservative-leaning National Review; Hannity.com, the site of Fox News talk show host Sean Hannity, who has steadfastly backed Trump and calls Mueller’s investigation “a house of cards that’s now crashing down,” and somewhat inexplicably, the New York Daily News.

Among a sample of Twitter users with strong connections to one of 10 groups along the political spectrum, the researchers found that 96 percent of Trump backers widely shared “junk” news and did so more than all other groups combined; the groups included military and gun rights supporters, liberals and other Democrats, and more. Among 13 similar categories of Facebook users, 91 percent of “hard conservatives” circulated junk news, also more than all other categories combined.

On the positive side, the researchers found that most Americans, including members of both the Democratic and Republican parties, were not targeted with junk news and tended not to share it.

The White House did not immediately respond to a request for comment on the study.