The U.N. children's agency is warning that a critical funding shortfall is threatening aid to 9 million Syrian children, both in their country and among the refugees in neighboring states.

UNICEF says the $220 million budget gap to its Syria relief programs is the worst it has faced since the war started. It appealed for $1.4 billion in 2017 to provide relief and education to children orphaned, displaced, wounded, or otherwise affected by the Syria war.

A UNICEF statement on Friday says that "without an injection of new funds, some critical and lifesaving activities ... are at a serious risk of being cut off, with grave consequences for Syrian children."

It says nearly 6 million children are in need in Syria and another 2.5 million require assistance in neighboring countries.