The United States today urged the divided UN Security Council to back an arms embargo and sanctions against South Sudan after the UN envoy reported that the war there is worsening.<br/>'<br/>US Ambassador Nikki Haley told the council that UN demands for a ceasefire, access for aid workers and a return to political talks had been "totally ignored" by President Salva Kiir's government.'<br/>'<br/>France and Britain backed the US call for tougher measures, but Russia said there was no need for an arms embargo and China urged the council to be more "positive" in its approach to South Sudan.''<br/>'<br/>UN envoy David Shearer earlier told the council that the situation was dire after more than three years of war.'<br/><br/>After gaining independence from Sudan in 2011, South Sudan descended into war in December 2013, leaving tens of thousands dead and more than 3.5 million people displaced.<br/>'''''''<br/><br/>