May 14 (UPI) -- The United States has imposed additional Iran-related sanctions, as the Trump administration negotiates with Tehran on a new nuclear weapons deal. The sanctions announced Tuesday by the U.S. Treasury target an Iranian oil smuggling network the Trump administration accuses of generating billions of dollars for the Tehran regime's military and proxy forces. Fifteen front companies, buyers and facilitators in Hong Kong, mainland China, the Seychelles and Singapore were hit by the