(CNN) During much-anticipated testimony Tuesday before the Senate Subcommittee on Consumer Protection, Facebook whistleblower Frances Haugen repeatedly pointed outside of the country for examples of how the social network could be used to dangerous ends -- so much so that lawmakers wondered during the hearing if they should meet to specifically discuss national security concerns.
The former product manager referenced a series of links between activity on Facebook and deadly violence in Myanmar and Ethiopia, and spying by China and Iran.
"My fear is that without action, divisive and extremist behaviors we see today are only the beginning. What we saw in Myanmar and now in Ethiopia are the opening chapters of a story so terrifying no one wants to read the end of it," Haugen said, referring to recent bloodshed in both countries.
Facebook admitted in 2018 that it failed to do enough to prevent the spread of posts whipping up hatred against the persecuted Rohingya minority in Myanmar. It has since vowed to limit the spread of "misinformation" in the country after a military coup earlier this year.
Asked by one senator whether Facebook is used by "authoritarian or terrorist-based leaders" around the world, Haugen responded that such use of the platform is "definitely" happening, and that Facebook is "very aware" of it.
Her last role at Facebook was with the company's counterespionage team, which she says "directly worked on tracking Chinese participation on the platform, surveilling, say, Uyghur populations around the world."
"You could actually find the Chinese, based on them doing these kinds of things," she said.
In March, Facebook's security staff revealed that Chinese hackers had targeted Uyghur activists and journalists living outside the country with fake Facebook accounts and malware.
Haugen's team also observed "the active participation of, say, the Iran government doing espionage on other state actors. This is definitely a thing that is happening," she said.
This summer, Mike Dvilyanski, Facebook's head of cyber espionage investigations, told CNN the company had disabled "fewer than 200 operational accounts" on its platform associated with the Iranian spying campaign, and notified a similar number of Facebook users they may have been targeted by the group.
Haugen blamed "a consistent understaffing of (Facebook's) counterespionage information operation and terrorism team" for the ongoing proliferation of such threats however, and said she was also speaking with other parts of Congress about them.
The revelation prompted Sen. Richard Blumenthal, a Connecticut Democrat, to suggest that national security concerns be explored more deeply in the future.
According to Haugen, engagement-based ranking -- which amplifies content that stirs users to react with likes, shares or comments -- is "literally fanning ethnic violence" in countries like Ethiopia, which is riven with deep regional and ethnic divides.
"I encourage reform of these platforms, not picking and choosing individual ideas, but instead making the ideas safer, less twitchy, less viral, because that is how we scalably solve these problems," she said.
While Facebook has developed measures to mitigate danger, they are unevenly applied across the world's languages, Haugen said.
"Facebook also knows, they have admitted in public, that engagement-based ranking is dangerous without integrity and security systems, but then not rolled out those integrity and security systems to most of the languages in the world. And that's what is causing things like ethnic violence in Ethiopia."
Following the hearing, Facebook issued a statement attempting to discredit Haugen and disputing "her characterization" of many issues.
"Today, a Senate Commerce subcommittee held a hearing with a former product manager at Facebook who worked for the company for less than two years, had no direct reports, never attended a decision-point meeting with C-level executives — and testified more than six times to not working on the subject matter in question," read the statement, tweeted by spokesperson Andy Stone.
"We don't agree with her characterization of the many issues she testified about. Despite all this, we agree on one thing; it's time to begin to create standard rules for the internet."