In the face of a possible escalation with Syria and Iran's efforts to obtain a nuclear weapon, parts of the country will shut down next month in what security officials say will be the largest emergency exercise in Israel's history. The drill, which is being organized by the newly-established National Emergency Authority, will take place over five days starting on Sunday, April 6. But first, on Tuesday, a first-of-its-kind hospital emergency exercise will take place to see how Ashkelon's Barzilai Medical Center would cope with a Grad missile hitting a five-story hospitalization building and an outpatient clinic's laboratory filled with toxic chemicals and a fire breaking out, requiring patients to be lowered from the roof. Around 100 firemen, 10 fire service vehicles and various other equipment, as well as doctors and nurses, will participate in the drill, to be held between 11 a.m. and 1:30 p.m. Preparations for the April exercise are being overseen by Deputy Defense Minister Matan Vilna'i. On the first day of the drill, Prime Minister Ehud Olmert will convene the cabinet in Jerusalem in response to an "enemy attack" and to decide on an Israeli response. Based on a lesson learned in the Second Lebanon War and in preparation for Iranian nuclear bombs and enemy use of chemical and biological weapons, the Israel Police, IDF Home Front Command and other military branches, all of the country's hospitals, the Fire and Rescue Service, Magen David Adom and other rescue services will all participate in the drill. According to officials involved in the planning, sirens will blast throughout the country. The rescue services will drill mass evacuations from "hit zones" - including mock chemical and biological attacks - and hospitals will drill their ability to provide medical treatment to thousands of wounded. One hospital that will practice dealing with a chemical attack will be Ha'emek Medical Center in Afula. "This is the biggest exercise in Israel's history," said a high-ranking defense official involved in the planning, while stressing that the exercise was not being conducted due to intelligence that war was imminent but rather as part of the lessons learned from the Second Lebanon War. Last Thursday, Vilna'i convened a meeting of directors-general from government ministries as well as their spokesmen to prepare the public relations side of the drill, and Israeli public relations during a real war. "This is not being done since we think there will be a war, but rather since we need to be prepared," the official said, adding that the government planned to hold such an exercise annually. All government ministries will participate in the exercise and they will hold a drill on one day during which they will direct all of their personnel to enter bomb shelters. Civilians will be asked to locate the public bomb shelter closest to their homes. Judy Siegel contributed to this report.