United Nations aid agencies said on Thursday that a $4.5 billion appeal to tackle the Syrian refugee crisis in 2015 was less than a quarter funded, putting millions of vulnerable people at risk, and had already led to cuts in vital assistance, Reuters reported. The shortfall has meant 1.6 million refugees have had their food assistance cut this year and 750,000 children are not attending school, the agencies and partner organisations said, calling on countries to deliver on their pledges. "We are so dangerously low on funding that we risk not being able to meet even the most basic survival needs of millions of people over the coming six months," the U.N. High Commissioner for Refugees Antonio Guterres said in the statement which represented more than 200 groups involved in the appeal. The refugee response plan is a $5.5 billion appeal, with $4.5 billion earmarked for U.N. agencies and non-governmental organisations. An additional $1 billion is intended to help regional countries hosting refugees.