The United Nations on Friday made its largest appeal ever -- for more than $5 billion -- for relief aid to Syrians across the country. "Syria as a civilization is unraveling, with as many as half of its citizens in need of urgent help as a result of this savage conflict," said Antonio Guterres, the world body's high commissioner for refugees, who announced the goal in Geneva. "The funds we are appealing for are a matter of survival for suffering Syrians, and they are essential for neighboring countries that are hosting refugees." More than 1.6 million Syrians have fled the country since the conflict began in March 2011; another 4.25 million are estimated to have been displaced inside it. UNHCR noted that it had appealed in December for $1 billion, but increased the figure after the number of refugees exceeded predictions. The announcement came as the U.N. Office for the Coordination of Humanitarian Affairs predicted that 3.45 million inside Syria could have crossed its borders by the end of the year and another 6.8 million people remaining inside Syria will need aid. That's nearly half of the nation, which has a population of 22.5 million, according to a report of CNN.