The Obama administration warned Egypt's military leaders Monday to hand over power to Mohammed Morsi -- the Muslim Brotherhood candidate who claimed victory in the presidential run-off election -- or risk losing billions of dollars in U.S. military and economic aid to the country, the Washington Post reports. Pentagon and State Department officials expressed concern with a last-minute decree by Egypt's interim military council to keep control of the country. "This is a critical moment in Egypt, and the world is watching closely," said State Department spokeswoman Victoria Nuland. "We are particularly concerned by decisions that appear to prolong the military's hold on power." Pentagon press secretary George Little said the U.S. would urge Egypt's military rulers "to relinquish power to civilian elected authorities." However, according to Zvi Mazel, former Israeli ambassador to Egypt, Morsi and the Muslim Brotherhood "want one and only one thing: to make Egypt Islamic and then go into all the other countries and to make a kind of caliphate and even go to the United States and Europe." Morsi vowed earlier this month that if elected, he would "achieve the Islamic conquest of Egypt for the second time, and make all Christians convert to Islam, or else pay the jizya [Islamic tax required of non-Muslims]."