WASHINGTON -- US President Donald Trump and Saudi Arabian King Salman bin Abd Al-Aziz "agreed to support safe zones in Syria" in a phone call on Sunday, the White House said, marking a potentially dramatic shift in Washington's posture toward the civil war there.The White House cast Trump's support for safe zones in Syria as just one of many policy ideas that will "help the many refugees who are displaced" from the war, which has prompted the worst refugee crisis since World War II. The two leaders also agreed to support similar humanitarian corridors in Yemen, where Riyadh has been waging a proxy war with Iran.The president is facing protests at home for banning Syrian refugees from entering the US homeland, as well as all nationals from seven predominantly Muslim nations: Syria, Iraq, Iran, Yemen, Sudan, Somalia and Libya.In their call, Trump also expressed his view that an international nuclear agreement brokered with Iran in 2015 should be "rigorously enforced"– a departure from his rhetoric during the campaign, in which he promised to shred the deal altogether.In a separate call with the crown prince of the United Arab Emirates, Sheikh Muhammad bin Zayid Al Nuhayyan, Trump also "raised the idea of supporting safe zones for the refugees displaced by the conflict in the region," the White House said in a statement.According to the administration, the crown prince agreed to support the initiative.