RNA - Sarah Leah Whitson, Middle East and North Africa director at Human Rights Watch (HRW), initially exposed the account's origin on Twitter Thursday.
"This is a US State Department funded account," she wrote.
IranDisinfo was apparently tasked with attacking critics of US President Donald Trump’s anti-Iran policies, including withdrawal from the international nuclear deal, reintroduction of illegal sanctions and stepping up threats against Tehran.
The account targeted an HRW researcher in search of the impacts of US sanctions on Iranian patients and their access to medicine.
"They're creating their own echo chamber, and it appears that they're funding it," Ryan Costello, policy director at the National Iranian American Council (NIAC), told the Middle East Eye as cited in a Friday report. "It strikes me as authoritarian, that you would have funding that's being used - either by intention or manipulated - to go after domestic opponents of the Trump administration. It's not something that's democratic or fair and balanced."
A US official also acknowledged that the account recently deviated from its official purpose of allegedly debunking disinformation about Iran.
"We have, however, identified recent tweets that fall outside the scope of the project to counter foreign state propaganda or disinformation," the official said. "Today, the Department suspended the funding for the Iran Disinfo project until the implementer takes necessary steps to ensure that any future activity remains within the agreed scope of work."
It is not clear how much money the State Department has spent for the anti-Iran project, whose operators are also unknown.
"They need to be completely transparent about the scope of the activities - who their grantees are on Iran programming and for what purpose," Costello said.
Under Trump, the US has been pursuing a “maximum pressure” campaign against Iran but to no avail. Tehran has slammed the US economic and psychological warfare, vowing to defend its interests in the region in case of US aggression.