It’s not just Russia. Other countries are also targeting American voters with disinformation on Twitter and other social media outlets, the Washington Post reported Thursday.

Former special counsel Robert Mueller said as much in Congressional testimony on Wednesday. After declaring that the Russians are still an active threat to U.S. election security, he added that “many more countries” have “developed similar capabilities, based in part on the Russian playbook,” the newspaper says.

Citing researchers, the Post identifies just some of those countries: Iran, Saudi Arabia, Israel, China, the United Arab Emirates and Venezuela.

“Researchers for FireEye and other firms have reported suspected Iranian disinformation on most major social media platform — Facebook, Instagram, YouTube, Google+ and others — and on standalone websites as well,” the newspaper says. “In May, FireEye also alleged that U.S. news sites may have been tricked into publishing letters to the editor penned by Iranian operatives.

Federal law enforcement, as well as the social media companies themselves, are working harder than ever to combat disinformation, the Post says, “typically by identifying and shutting down networks of fictitious, foreign-based accounts….”

But for every action there is counter-action.

As the companies crack down, the tactics of disinformation teams rapidly shift to improve operational security and more effectively evade detection,” the Post says.

Some, though not all, of the culprit countries appear to favor keeping President Trump in office.

So their biggest target is dead ahead: the 2020 election.