UNITED NATIONS (AFP) ― U.N. relief efforts in war-torn Syria are struggling to reach 40 percent of civilians in need and face a major funding shortfall, a senior aid official said Wednesday.

As the war heads toward a fifth year, some 4.8 million Syrians or around 40 percent of the total 12.2 million people in need of help are difficult to reach, said sssistant secretary-general for aid Kang Kyung-wha.

Kang told the Security Council that U.N. agencies were unable in December to deliver food to the Raqa and Deir Ezzor areas controlled by the Islamic State group and to towns besieged by Syrian government troops and opposition forces.

Cross-border deliveries of aid have reached over 700,000 people, but “despite these efforts, needs continue to outpace response,” said Kang.

The United Nations is requesting $2.9 billion this year to fund aid operations for Syria, where fighting has led to what Kang described as “one of the worst displacements of people the world has seen in decades.”

U.N. agencies received less than half of the amount requested for last year, leaving “hundreds of thousands” of civilians without aid during the harsh winter months, said Kang.