California-based Twitter said it was releasing detailed data on previously disclosed misinformation efforts to allow researchers to gain more insight into the campaigns.

"In line with our strong principles of transparency and with the goal of improving understanding of foreign influence and information campaigns, we are releasing the full, comprehensive archives of the tweets and media that are connected with these two previously disclosed and potentially state-backed operations on our service," said a statement from Twitter trust and safety chief Vijaya Gadde and site integrity head Yoel Roth.

"We are making this data available with the goal of encouraging open research and investigation of these behaviors from researchers and academics around the world."

Twitter last year banned some Russia-based accounts accused of spreading misinformation during the 2016 US election, and earlier this year acknowledged that hundreds of accounts from Russia and Iran were engaged in manipulation efforts.

Facebook has uncovered similar efforts and has stepped up its efforts to curb foreign influence.

In Wednesday's statement, Twitter said influence campaign efforts came from 3,841 accounts originating in Russia, and 770 potentially originating in Iran.

They included more than 10 million tweets and more than two million images and videos from as early as 2009.

"It is clear that information operations and coordinated inauthentic behavior will not cease," Twitter said.

"These types of tactics have been around for far longer than Twitter has existed -- they will adapt and change as the geopolitical terrain evolves worldwide and as new technologies emerge. For our part, we are committed to understanding how bad-faith actors use our services."

Researchers at the Atlantic Council, who had early access to analyze the Twitter data, the influence campaigns sought to exploit vulnerabilities in a polarized electorate.

"The Russian and Iranian troll farm operations show that American society was deeply vulnerable, not to all troll farm operations, but to troll accounts of a particular type," said a blog post from the group's Digital Forensic Research Lab.

"That type hid behind carefully crafted personalities, produced original and engaging content, infiltrated activist and engaged communities, and posted in hyper-partisan, polarizing terms."