(TNS) — The three southwest Kansas men recently convicted in a militia plot to bomb Somali immigrants in Garden City may have been motivated by Russian manipulation of U.S. social media, a terrorism expert says.

Brian Levin, director of the Center for the Study of Hate and Extremism, said the domestic terrorism attack was being planned at the same time the Russians were conducting a cybercampaign that included posting material on Facebook designed to heighten racial tension in the United States.

And, he said, his center has found that hate crimes spiked after the Russian operatives ramped up the volume of racially charged posts in the months leading up to the 2016 election.

Prosecutors said the plot to attack the apartment complex in Garden City where Somali immigrants lived and worshiped was planned for the day after the election. The plot was thwarted by federal authorities in October 2016.

"Here's a militia group that was active on social media and they were going to do their attack the day after Election Day at a time when the Russians were engaging in a stealth cyberattack on our democracy," Levin said. "We don't know for sure if there's a connection to this effort by Russia, but at the very least, they were adding gasoline on a fire that they knew would take place.

"Social media has been weaponized, and these militia folks were People's Exhibit A of how that could happen. And this is now something that authorities have to be aware of."

News of the Russian interference surfaced in February, when special counsel Robert Mueller indicted 13 Russians and three companies on charges that they conspired to meddle in the 2016 election.

Prosecutors said the operatives placed ads on social media platforms including Facebook and Instagram before and after the election. The ads, prosecutors said, were bought by the Russian-based Internet Research Agency and designed to sow discord in the U.S. political system.

Facebook has estimated that the Russian campaign reached 146 million people on Facebook and Instagram through the ads and other posts.

In May, Democrats on the House Intelligence Committee released about 3,500 of the fraudulent ads that had been placed by the Internet Research Agency, the company at the center of the Mueller indictment.

Many of the posts were anti-Muslim. One referred to Islam as "a culture of violence." Another, which had been shared 12,000 times on Facebook, said that "America's slowly but surely shifting towards turning into islamic state."

One, which had more than 193,000 "likes" on Facebook, was posted by a group called Stop A.I. (Stop All Invaders). It said: "We are against illegal immigration and Islamization of America!"

Another post by the Stop A.I. group depicted a Mexican immigrant's face on the body of a boll weevil, a beetle that destroys crops. The insect held a knife and fork in its hands. Next to the drawing were the words, "It's time to get rid of parasites!"

Two of the conspirators in the Kansas militia plot posted similar comments about immigrants on their Facebook pages in the months leading up to their arrests.

On July 4, 2016, Patrick Stein posted: "I'm a RACIST for criticizing our COCKROACH loving potus and his MUSLIM BROTHERHOOD CABINET!! I'm a TERRORIST because I'm not afraid to stand up for what's right. ... I'm a TROUBLEMAKER for supporting the 2nd Amendment."

On Nov. 17, 2015, Curtis Allen wrote: "Ok folks, here is a small request. While your out and about doing what ever it is sheeple do?? Make a note of where you see muslims shopping, hanging out, maybe you know where a mosque is located, maybe you have a muslim neighbor?? Compile this list now, after our next Islamic attack I am going to get on here and ask for it!! I'm just trying to get you to be involved a little ahead of time. If we know where these people are and there locations ahead of time it will make the initial response much more timely."

Allen continued: "We as Kansas have to take the next step here!! If anyone hears they are bringing these refugees into our state we have to spread the word imeadiatly!! We can meet buses at state lines and shut them down or take more drastic matters to stop this invasion! Reach out to everyone you know that might get a lead to such travels and put out the warning."

Allen, Stein and Gavin Wright — who called their small militia "The Crusaders" — were found guilty in April of conspiracy to use a weapon of mass destruction and conspiracy to violate the civil rights of residents of the Garden City apartment complex. Their sentencing is scheduled for Sept. 6.

Levin said it's possible the Kansas militia conspirators saw and were even influenced by the Russian posts.

Last month, USA Today published a report based on its examination of the 3,517 Russian ads. The study found that the Internet Research Agency overwhelmingly focused its social media campaign on race, promoting ads designed to inflame racial tensions in the U.S.

According to the report, the number of divisive racial ad purchases averaged about 44 per month from 2015 through the summer of 2016, then rose significantly in the run-up to the November election.

Between September and November 2016, USA Today found, the number of race-related spots increased to 400, with another 900 posted on social media after the election and continuing through May 2017.

Levin's organization, based at California State University-San Bernardino, took the research a step further, comparing the USA Today findings with the FBI's 2016 hate crime statistics. Levin said the analysis found a clear connection between the frequency of the racially motivated Russian ads and the number of bias crimes reported. As the number of racially divisive Russian ad purchases rose, they found, so did the number of hate crimes that were reported.

The center's new report, "Hate Crime Rise in U.S. Cities and U.S. Counties in Time of Division and Foreign Interference," also found that hate crimes reported to police in America's 10 largest cities rose 12.5 percent in 2017. The totals were up for the fourth year in a row, the study found, and were the highest in more than a decade — even as crime in general across the nation slightly declined.

Levin said that although the correlation alone doesn't prove the Russian ads caused the spike in crimes, the issue is definitely a concern.

"This was a huge operation, with almost 500 fake accounts that spewed thousands of ads that may have hit up to 146 million Americans," he said. "One ad alone had 1.2 million impressions.

"When you have millions of people being exposed to something like this, under certain circumstances, hate offenders will latch on to those prejudices and then act on them."