The United Nations plans to make its first air drops of food and other aid in Syria, to Deir al-Zor, an eastern city of 200,000 besieged by Islamic State militants, the chair of a U.N. humanitarian task force said on Thursday.

U.N. aid agencies do not have direct access to areas held by Islamic State, including the city, where civilians face severe food shortages and sharply deteriorating conditions.

Speaking a day after U.N. road convoys reached five areas, some besieged by government forces and others by rebels, Jan Egeland said the organization's World Food Program (WFP) had a "concrete plan" for carrying out the Deir al-Zor drop in the coming days.