Facebook announced Tuesday it had removed hundreds of fake accounts originating in Iran and Russia from its own platform and from Instagram.
The accounts were part of "distinct campaigns" but were not linked or coordinated, the technology giant said.
"We ban this kind of behaviour because we want people to be able to trust the connections they make on Facebook. And while we're making progress rooting out this abuse, as we've said before, it's an ongoing challenge because the people responsible are determined and well funded," the company said in a statement.
Cybersecurity firm FireEye gave Facebook a tip in July which led to an investigation into Liberty Front Press (LFP), a network of social media pages which originated in Iran and targeted people in the Middle East, Latin America, Britain and the US.
The first LFP accounts were created in 2013, some were linked to Iranian state media and from 2017 they began primarily posting political content while hiding their locations.
LFP pages also began hacking people's accounts from 2016.
Another set of pages, the first of which began in 2011, was also found to have spread political content about the Middle East in Arabic and Farsi as well as information on the US and Britain in English.
Facebook added that it has removed pages, groups and accounts linked to Russian military intelligence services.
"We're working closely with US law enforcement on this investigation, and we appreciate their help. These investigations are ongoing – and given the sensitivity we aren't sharing more information about what we removed," head of cybersecurity policy Nathan Gleicher said.
