(Bloomberg) -- Executives from Facebook Inc., Twitter Inc. and Google’s YouTube told U.S. lawmakers they are combating disinformation on a range of subjects including the 2020 election and have taken down video, posts and messages deemed false and a risk to health and safety.

Google’s YouTube has removed 200,000 videos and more than 100 million advertisements in an effort to stem disinformation about the coronavirus pandemic and prevent advertisers from profiting, Richard Salgado, the director of law enforcement and information security at Alphabet Inc.’s Google, said Thursday in prepared testimony for a House Intelligence Committee hearing.

Twitter has tracked the threat of disinformation related to recent protests on racism and police brutality spurred by the death last month of George Floyd at the hands of police in Minneapolis, said Nick Pickles, director of global public policy strategy and development.

“The public conversation on Twitter has highlighted the deep-rooted nature of issues related to race, justice, and equality,” Pickles said, according to prepared testimony. “While we have not seen evidence of concerted foreign state-backed efforts to manipulate the public conversation in recent weeks, we remain vigilant.”

Committee Chairman Adam Schiff, a Democrat from California, scheduled the hearing to focus on the influence of foreign actors on the social networks. In his prepared opening remarks, he cited threats of manipulation from Russia, China and Iran and asked: “Will your companies be able to keep up?”

“I am also concerned because the nature of your platforms, all of them, is to embrace and monetize virality. The more sensational, the more divisive, the more shocking or emotionally charged, the faster it circulates,” Schiff said.

Each of the platforms described what they are doing to try to curb disinformation ahead of the 2020 election. For example, Google is building on the trainings about email and campaign website security that it provided to 1,000 campaign professional as well as the eight major Republican and Democratic political committees, Salgado said.

Facebook currently has 35,000 people working on safety and security -- three times the number in 2017 -- according Nathaniel Gleicher, the company’s head of security policy. The company has studied the conversation on Facebook surrounding 200 elections around the world as it prepares for November, he said.

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