The US took control of 27 internet propaganda domains operated by Iran's Islamic Revolutionary Guard Corps as Washington continued to frustrate on Tehran's efforts spread its message.
They were being used in breach of US sanctions on Iran. Four of the 27 operated as news outlets while trying to influence US users, while the rest took aim at audiences in other countries.
Last month, the US shut 92 domains linked to the IRGC that were used for similar purposes.
“Within the last month we have announced seizures of Iran’s weapons, fuel, and covert influence infrastructure,” said John Demers, assistant attorney general for national security.
“As long as Iran’s leaders are trying to destabilise the world through the state-sponsorship of terrorism and the taking of hostages, we will continue to enforce US sanctions and take other legal steps to counter them.”
Mr Demers said work to stop Iran's disinformation campaign would continue.
“We cannot allow Iran's attachment to fake news to overtake our commitment to the rule of law,” he said.
Craig Fair of the FBI said the operation was carried out in collaboration with social media companies Google, Facebook and Twitter.
“The FBI is aggressively investigating any evidence of foreign influence and the unlawful spread of disinformation by hostile nations," Mr Fair said.
"Today, we seized 27 additional domains that Iran’s IRGC was illegally using in attempt to manipulate public opinion in other countries, including the United States."
