The Trump administration will not sign an international pledge by governments and online services to combat extremist content online. The Christchurch Call is named after the New Zealand city where a terrorist livestreamed the shooting deaths of 50 Muslims in March.

The statement is being formally released today as part of an international summit in Paris. It will bear the signatures of more than a dozen nations, including Australia, Canada, France, Germany, Japan, New Zealand, and the United Kingdom. Leading technology companies, including Facebook, Google, Microsoft, and Twitter, have also signed on. But not the US government.

"The United States stands with the international community in condemning terrorist and violent extremist content online in the strongest terms," the White House said in an emailed statement Wednesday. The US government says it will "continue to support the overall goals reflected in the Call," however, it is "not currently in a position to join the endorsement."

The White House didn't explain why it couldn't support the statement, but the First Amendment seems to be a significant concern, the Washington Post reports. "We maintain that the best tool to defeat terrorist speech is productive speech," the White House said yesterday.

Under the First Amendment, American law protects a broader and more robust concept of free speech than the law in most other countries. Other countries strictly regulate hate speech, pornography, political advertising, and other controversial content. By contrast, the US Supreme Court allows speech restrictions only in a handful of narrow categories, such as child pornography, defamation, and incitement to violence.

Ahead of Wednesday's release of the international statement, Facebook announced that it would be expanding its "one strike" policy for Facebook Live. Anyone who commits one of several major infractions under Facebook rules—for example by linking to pro-terrorism propaganda—will now be banned from using Facebook Live for a period of time (such as 30 days) on the first offense. Facebook says that such users will also be restricted from buying ads on the platform.