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Facebook, Twitter, Microsoft and YouTube have signed on to new rules to tackle online hate speech.

The Internet titans agreed on Tuesday to a new code of conduct by the European Union that takes aim at illegal hate speech and terrorist propaganda posted online. Under the new rules, they have committed to reviewing within 24 hours of receipt the majority of notifications about a social media post that may contain hate speech. They've also agreed to remove the post if necessary.

Under the rules, the companies will also communicate with one another, with governments and with law enforcement agencies about keeping up with potential abuse.

"There's no place for hate speech on Facebook," said Monika Bickert, head of global policy management at Facebook. "We urge people to use our reporting tools if they find content that they believe violates our standards so we can investigate. Our teams around the world review these reports around the clock and take swift action."

Karen White, Twitter's head of public policy in Europe, echoed the sentiment. "We remain committed to letting the tweets flow," she said. "However, there is a clear distinction between freedom of expression and conduct that incites violence and hate."

In addition to removing abusive posts, the EU and the big companies will look to balance hate speech by promoting "independent counter-narratives" and supporting educational programs that "encourage critical thinking."

Twitter wants to "leverage the platform's incredible capabilities to empower positive voices, to challenge prejudice and to tackle the deeper root causes of intolerance," White said.