Mothers and children crying. People running. The air thick with tear gas. This was the scene at the US-Mexico border on Sunday after a peaceful protest quickly exploded into violence and confusion. American border agents fired tear gas into a crowd that involved women and small children at the San Ysidro crossing, which separates Tijuana, Mexico, and San Diego, right here in California. A photo that showed a mother and her children and her young children being tear-gassed sparked international outrage after being posted onto multiple news sites.

While President Trump and Secretary of Homeland Security, Kirstjen Nielsen, have defended the action, the whole issue has sparked a wildfire of national rage, and The Foreign Ministry of Mexico has asked the United States for a full investigation.

Prominent U.S. politicians like Gavin Newsom, the governor-elect of California, have denounced the incident. Not to mention Geoff Gilbert, a professor of humanitarian law and international human rights at the University of Essex in Britain, said that while the U.S. had the right to control the flow of people who want to come in the country, the peaceful protest did not “give authorities in the United States the right to fire tear gas into another country.” Gilbert consulted the United Nations Charter on the sovereign rights and obligations of member countries, and Article 2 says that members “shall refrain in their international relations from the threat or use of force against the territorial integrity” of other members.

The event was a new low for even the Trump administration because while there have been 126 uses of tear gas at the US-Mexico border since 2012, it has never been used on this many people at once. Defending their actions, the Customs and Border Protection commissioner said that the migrants were throwing “dozens of projectiles” at the border agents. Four officers received minor injuries.

As of now, this all of the information we know of the incident: The Foreign Ministry of Mexico has asked the United States for a full investigation, and multiple humans rights organizations have denounced the border incident. While the investigation that the Mexican Foreign Ministry asked for may yield multiple leads, the U.S. and the border agents who shot the tear gas have faced no serious consequences.