U.N. officials say Syrian government approval is needed before the World Food Program can carry out air drops and airlifts of food into besieged areas of the war-torn country.

Humanitarian aid adviser Jan Egeland and Ramzy Ramzy, a deputy to U.N. envoy Staffan de Mistura, spoke to reporters in Geneva on Thursday.

A deadline set by world powers for the WFP to "immediately carry out a program for air bridges and air drops for all areas in need" in Syria expired on Wednesday.

Egeland says the companies who are subcontracted to carry out airlifts for WFP require government authorization.

He says the government in Damascus hasn't provided permission for nearly all of the areas in need.