Facebook announced Oct. 26 that it has taken down 82 pages, groups and accounts originating in Iran that spread political propaganda targeting the United States and the United Kingdom.

More than 1 million users followed the fake pages, according to Facebook, and its discovery comes amid a flurry of allegations by U.S. officials regarding political propaganda from Iran, China and Russia.

“We are concerned about ongoing campaigns by Russia, China and other foreign actors, including Iran, to undermine confidence in democratic institutions and influence public sentiment and government policies,” read an Oct. 19 joint statement from four U.S. government agencies.

“These activities also may seek to influence voter perceptions and decision-making in the 2018 and 2020 U.S. elections."

Facebook’s announcement is another example of propaganda by Iran, Russia and China that has targeted the political system of Western nations. Complicating a solution is the fact that the three countries have taken evolving approaches in their disinformation campaign targeting the U.S., according to experts and American officials.

The great majority of Iranian disinformation discovered by Facebook “consisted of divisive and polarizing content,” said a post by the Atlantic Council’s Digital Forensic Research Lab.

Examples of the campaign include posts that promoted violence, distrust of the American political system and racial tension.

Facebook’s announcement is the second time the company has identified fake Iranian content. The social media giant also removed more than 652 pages, accounts and groups for propaganda in August.

“Their behavior showed how much they had adapted from earlier operations, focusing more on social media than third-party websites and becoming much more engaging,” wrote the Atlantic Council’s Digital Forensic Research Lab.

Experts said the Iranian activity is similar to Russian tactics of spreading disinformation on Facebook.

The Iran-based posts “behaved the same way the Russian operation did, posting engaging content, including positive messaging consistent with the communities they were trying to infiltrate,” Ben Nimmo a senior fellow at the Atlantic Council, wrote in a Twitter post.

Experts and U.S. officials also said that Russia is trying to seep confidence in the U.S. political system by spreading misinformation and discord.

For years, members of the Russia-backed Internet Research Agency “operated social media pages and groups designed to attract U.S. audiences. These groups and pages, which addressed divisive U.S. political and social issues, falsely claimed to be controlled by U.S. activists,” said a February indictment by special counsel Robert Mueller.

Top U.S. officials have contrasted Russian propaganda activity with Chinese efforts. There is no public evidence that China has undertaken a disinformation campaign on Facebook like Russia or Iran. Rather, U.S. officials say Beijing is trying to use traditional American media to shape public opinion.

“Russia’s objectives here are to undermine the system. China’s objectives are to manipulate the system,” Chris Krebs, under secretary at Homeland Security, told reporters Oct. 23.

For example, China placed a four-page ad in the Iowa-based Des Moines Register in September that laid out risks of a trade war between Washington and Beijing.

Krebs compared disinformation today to historical propaganda.

“Ideally, we get to a position where much like in the ’70s and ’80s when Pravda was again an instrument of the Kremlin and the USSR, it was immediately discounted because it was clearly a propaganda piece,” Krebs told reporters.

“We need to make sure that that level of awareness is out there that if you spot something you say, ‘Yep, that’s government propaganda.’”