New York City could be the next site of a chemical assassination attempt if world leaders fail to punish Russia for its alleged role in poisoning of a former spy in the United Kingdom, U.S. Ambassador to the United Nations Nikki Haley warned Wednesday.

“If we don’t take immediate concrete measures to address this now, Salisbury will not be the last place we see chemical weapons used,” Haley told the United Nations Security Council. “They could be used here in New York, or in cities of any country that sits on this Council. This is a defining moment.”