The U.S. will not sign onto the "Christchurch call to action" against online extremism expected to be released Wednesday, citing concerns that the pact would violate free speech protections in the First Amendment, the Washington Post reports.

The big picture: The document, negotiated by New Zealand and French officials as a commitment to study and stop the spread of online extremism that motivated the Christchurch mosque shootings earlier this year, is expected to be signed by Australia, Canada and the U.K., among others. It also has the support of major U.S. tech companies, including Facebook and Google, whose platforms were used to livestream and host videos of the attack.

What they're saying: The White House indicated on Tuesday that it would not support the effort, saying, "We continue to be proactive in our efforts to counter terrorist content online while also continuing to respect freedom of expression and freedom of the press. Further, we maintain that the best tool to defeat terrorist speech is productive speech, and thus we emphasize the importance of promoting credible, alternative narratives as the primary means by which we can defeat terrorist messaging."

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