NEW YORK (AP) — Lawmakers grilled executives Facebook, Google’s YouTube and Twitter on Wednesday about what the companies are doing to prevent terrorists from using their platforms to spread propaganda and recruit new followers.

The Senate’s commerce, science and transportation committee hearing comes amid growing government scrutiny over misuse of social media platforms and questions about what the companies are doing to prevent it.

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The hearing came after November’s exhaustive congressional hearings on what the companies knew — and did — about Russia’s efforts to meddle with the 2016 U.S. elections using their platforms.

“Terrorism and social media is a challenging and I think pressing subject. And I recognize technology companies cannot solve this alone, but they must do more,” said Senator Tom Udall (D-New Mexico).

Companies like Twitter claim they have made progress, but securing their networks is still a challenge.

“What’s the number? How many fake accounts do you have?” Senator Brian Schatz (D-Hawaii) asked Twitter Director of Public Policy Carlos Monje.

“Fewer than five percent of the accounts on Twitter are fake accounts,” replied Monje.

“If you know they’re fake, what’s the issue here?” asked Schatz.

Monje responded, “Uhh, they keep coming back.”

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To prove they have made some headway, the companies provided some hard numbers Wednesday.

During the first half of last year, Twitter says it suspended just under 300,000 accounts that promoted terrorism.

YouTube says since June, it has gotten rid of 160,000 videos and 30,000 channels that promote violent extremism.

Additionally, Facebook said 99 percent of ISIS and Al Qaeda-related terror content is removed before anyone reports it.

“If we become aware of a threat of violence, a credible threat of imminent harm to somebody, we proactively reach out to law enforcement authorities,” said Monika Bickert, Head of Global Policy Management at Facebook

Lawmakers acknowledged that the companies, especially Google and Facebook, have come a long way when it comes to weeding out extremist material.

But not everyone is making as much progress as the committee had hoped.

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“I am disappointed by Google’s written response. It essentially blew off my concerns by saying the nature of the platform made it difficult to know who has viewed its content,” said Senator Richard Blumenthal (D-Connecticut).