The United States reimposed international sanctions on Iran that the United Nations lifted in 2016 as part of the nuclear agreement, or Joint Comprehensive Plan of Action (JCPOA). However, France, Germany, and the United Kingdom, as well as Iran, said that the reimposition lacked legal validity because the United States is no longer a party to the agreement. The United States threatened to use domestic authorities to punish countries that fail to enforce the U.N. sanctions. The U.S. move is a response to a failed effort by the United States to extend a U.N. arms embargo on Iran set to expire on October 18.