Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. UN: Security Concerns Prevent Aleppo Evacuations by VOA News The United Nations was forced to postpone planned medical evacuations in east Aleppo Friday because security assurances were not given by groups fighting in the city. "Medical evacuations of sick and injured could unfortunately not begin this morning as planned because the necessary conditions were not in place," said Jens Laerke, spokesman for the United Nations humanitarian office. Laerke didn't specify which groups failed to honor the humanitarian pause ordered by Russia a day earlier, saying only that the U.N. and the people of Aleppo were in an "astronomically difficult situation." Russia on Thursday ordered that a humanitarian pause in Aleppo be extended for another 24 hours. Syria and Russia stopped airstrikes on Aleppo Tuesday and the pause in fighting had been due to end at 7 p.m. local time Thursday. As part of the truce, the Syrian army has opened up eight corridors civilians can use to safely exit the city. Two of those corridors have also been opened up to rebel fighters who wish to lay down their weapons and flee; one leading to Turkey and the other a pathway to the rebel-held Syrian province of Idlib. The United Nations said about 250,000 civilians are in desperate need of supplies on Aleppo's eastern side and hundreds of others who urgently need of medical care need to be evacuated. U.N. and Red Cross trucks packed with supplies have been sitting near the Turkish border for weeks, awaiting guarantees they can safely deliver relief supplies. Syrian and Russian warplanes had been bombarding the area in an attempt to reclaim Aleppo from rebels.