Due to increased pressure by international medical and humanitarian agencies, the IDF has tightened open-fire orders regarding Palestinian ambulances suspected of being involved in terrorist activity, The Jerusalem Post has learned. As part of the army's increasing coordination with international humanitarian agencies, IDF soldiers in Gaza have been told to exercise extreme sensitivity to the movement of ambulances in the battle zones. While there have been attacks on ambulances and medical crews in Gaza, there have also been Israeli reports of Hamas making use of ambulances for military purposes. According to the United Nations Relief and Works Association (UNRWA), 13 medical personnel have been killed in Gaza since the onset of military operations on December 27, and attacks on medical personnel and ambulances have hampered the organizations' ability to assist the wounded. The Red Cross has also complained that military operations are hampering their ability to carry out evacuations. Ambulances invariably make their way into many of the spontaneous cross-fires and 'hot zones' that pop up in the Gaza Strip, and are thus very vulnerable. The Post has also learned that the IDF is currently deploying 25 humanitarian officers currently deployed as liaisons between the army and international humanitarian organizations in the Gaza Strip. The officers, mostly experienced colonels and majors, are under the command of the IDF's Joint Humanitarian Coordination Center, commanded by Brig.-Gen. Baruch Spiegel. In the field, the officers are attached to the forces inside the Strip all along the chain of command up to brigade level. The soldiers, all of whom speak Arabic and English, act as troubleshooters and coordinators of the IDF's humanitarian efforts in Gaza. They are armed and embedded with units in the field and can usually be found close to brigade commanders at forward command posts where they advise brigade commanders of their humanitarian responsibilities in real time, in the same way as intelligence and legal officers advise their commanders of other operational aspects. They are mostly reservists from the Coordinator of Government Activities in the Territories [COGAT] who in civilian life are doctors and lawyers. The IDF and UNRWA are operating a joint database detailing the movement and location of displaced Gazans. The number of people who have fled their homes in Gaza remains unknown, but is estimated in the tens of thousands. As of the evening of January 12, UNRWA was operating 38 emergency shelters, with 35,520 displaced people. UNRWA informs the coordination center every time there is a change in the movement of Gazan civilians into and between shelters, who then passes that information on to the IDF fighting units to make sure each commander knows the location of concentration of civilians. In an effort to avoid collateral damage, areas with large concentrations of displaced civilians can be marked as "no-fire" zones, Spiegel told the Post.