In Paris, the leaders of France and New Zealand on Wednesday unveiled an agreement to combat online extremism. The so-called Christchurch Call is named after the New Zealand city where, in March, a white nationalist gunman killed 51 worshipers at two mosques—and live-streamed the massacre on Facebook. This is New Zealand Prime Minister Jacinda Ardern.

Prime Minister Jacinda Ardern: “The social media dimension to the attack was unprecedented. And our response today, with the adoption of the Christchurch Call, is equally unprecedented, as well. Never before have countries and tech companies come together in the wake of an horrific attack to commit to an action plan that will deliver, collaboratively, work in new technology built to make our communities ultimately safer.”

So far, the Christchurch Call has the support of 16 countries, the European Commission and eight tech giants. But the Trump administration said Wednesday it was “not currently in a position to join the endorsement.” The White House cited concerns the agreement could violate the First Amendment. In a New York Times opinion piece last weekend, Prime Minister Ardern wrote she supports free speech rights but “that right does not include the freedom to broadcast mass murder.”