The Kremlin has called US President Joe Biden's ban on Russian oil and fuel imports a declaration of an "economic war."  Biden announced that the  import ban is a "powerful blow" against Russia's ability to fund its ongoing offensive against Ukraine. Biden said the U.S. was acting in close consultation with European allies, who are more dependent on Russian energy supplies and who he acknowledged may not be able to join in immediately. What impact will this US action have on Russia? Kan reporter Naomi Segal put the question to Dr. Yonatan Freeman, an international relations expert at the Hebrew University of Jerusalem.