Reuters reports the United States said on Monday it had imposed sanctions on four people affiliated with Islamic State and another militant group, including two Russian nationals and a Briton. The U.S. Treasury Department said three Islamic State supporters and a member of the so-called Caucasus Emirate were designated as foreign terrorists. The designations allow the U.S. government to freeze their assets and bars U.S. citizens from dealing with them. The four were also put on the United Nations al-Qaeda sanctions list, a Treasury statement said. The action "highlights the ramp-up in U.S. and international efforts to aggressively target and destroy ISIL," said Daniel L. Glaser, the Treasury's assistant secretary for terrorist financing, referring to Islamic State by an acronym.