UN Syria envoy Staffan de Mistura at a press conference in Geneva on Thursday. Pic/AFP

Geneva: The ceasefire in the Syria war is holding for the most part, but humanitarian aid is still not getting through to besieged areas where food is running out, UN envoy Staffan de Mistura said on Thursday, voicing concern that 23 buses and Syrian drivers used in recent evacuations were being stopped from leaving the villages of Foua and Kefraya in Idlib province by armed groups. He called for them to be allowed to leave.