Former special counsel Robert Mueller warned on Wednesday that Russia and “many more countries” were likely to spread disinformation by targeting Americans which could influence voters in the 2020 election. These mirrored the findings of a broad range of independent researchers, according to The Washington Post.

“It wasn’t a single attempt. They’re doing it as we sit here, and they expect to do it the next campaign,” said Muller in his congressional testimony.

A cybersecurity firm called FireEye, along with other firms in the field, have been reporting disinformation being disseminated on major social media platforms like Facebook, Instagram, and YouTube.

In May, FireEye also alleged that U.S. news sites may have been tricked into publishing letters to the editor penned by Iranian operatives, The Washington Post reported.

Earlier this month, Forbes reported that after the U.S. shot down an Iranian drone in the Straight of Hormuz, it was discovered that an Iranian-led hack was targeting millions of unpatched Microsoft Outlook systems in the U.S.

On the heels of that report, Microsoft announced that it notified 10,000 of its customers that their systems were potentially compromised by a cyberattack in the past year — primarily via attacks from Russia, Iran, and North Korea, according to The Wall Street Journal.

#Iran, other countries prepared to follow #Russia's disinformation playbook in 2020, researchers say https://t.co/ea8pEXFInD — Andrej Matisak (@matisaksk) July 25, 2019

Disinformation researchers, such as FireEye, say that the Iranians are using Russian-style “sock puppets” which are the type of fake online profiles Russians used while attempting to influence the 2016 presidential election.

Twitter has shut down more than 7,000 of these accounts from Iran this year.

According to The Washington Post, that could mean that U.S. voters are likely to be targeted by more foreign disinformation more than ever before.

“Multiple foreign actors have demonstrated an ability and willingness to leverage these kinds of influence operations in pursuit of their geopolitical goals,” said Lee Foster, head of the cybersecurity team at FireEye. “We risk the U.S. information space becoming a free-for-all for foreign interference if, as a society, we fail to get an effective grasp on this problem.”

Though the method of delivery is similar to Russia’s, Iranian tactics are a little different.

The Russians infiltrated the online conversation groups with topics such as anti-immigration, African Americans, veterans, and evangelical Christians writing messages that blended into those online communities.

Iranian tactics that have been discovered thus far aren’t that sophisticated. Their message is simple. They just oppose one issue on many platforms.

As public media platforms attempt to deal with these tactics, researches told The Washington Post that this might only be a small portion of a bigger and more covert operation.

Countries that have been identified as fostering online misinformation operations include Saudi Arabia, Israel, China, the United Arab Emirates, and Venezuela, researchers say.