The IDF began on Tuesday staging its largest civil defense exercise ever, simulating unconventional and rocket attacks in an operation meant to demonstrate lessons security and rescue forces learned from last summer's war with Hizbullah. In the two-day operation, which will involve thousands of police and soldiers, security forces and emergency crews were to respond to simulated attacks on seven different locations, including a chemical attack on a school and a rocket strike on a Tel Aviv power station. Later Tuesday, an emergency siren was to sound throughout central Israel as part of the exercise. "We are demonstrating through such an exercise the lessons we learned in the past war," OC Home Front Command Maj.-Gen. Yitzhak Gershon told reporters. Critics have said the army and home front command did not do enough to protect the North from the nearly 4,000 rockets that Hizbullah rained on the area during the war. "This exercise is part of building the preparedness of the army, the police, the state," Deputy Defense Minister Ephraim Sneh told reporters. "The integration of all of them is one of the most important lessons of the war." A total of 5,000 police, or 25 percent of the overall operational force, will participate in the exercise, police spokesman Micky Rosenfeld said. About 130 communities will be involved in the operation, which is meant to improve coordination between the different security forces and rescue crews, Rosenfeld said. The sirens will not be heard in northern Israel, for fear they might spark panic because the border is still tense following the war, nor in southern Israel, where Kassam rockets shot by Palestinians from the Gaza Strip frequently fall.