A technical failure led to two Grad rockets striking Be'er Sheva on Sunday afternoon, Col. Tzvika Haimovich, head of the IDF's active aerial defense system, told Haaretz.

One rocket hit a school that was empty at the time and the other struck a parked car in a residential neighborhood.

Open gallery view Israelis examining the damage caused to the wall of a school in Be'er Sheva after it was hit by a rocket fired by Palestinian militants on March 11, 2012. Credit: AFP

"Unfortunately, the incident in Be'er Sheva happened because of a technical failure in one of the system's components," Haimovich said. "It happened exactly when a rocket was in the air. We are doing everything to make sure there are no failures but it would be irresponsible and unprofessional of me to say there is 100 percent protection."

The Iron Dome system has intercepted 40 rockets since Friday. More than 90 rockets have fallen in Israeli territory during that time. The Iron Dome is designed to intercept only rockets identified as heading toward populated areas.

next previous 20 of 20 | Palestinians inspecting the effects of a motorcycle bombing executed by the IAF, Khan Younis, Gaza, March 10, 2012. Credit: AFP 1 of 20 | An Iron Dome missile battery in action on Monday, March 12, 2012. Credit: AFP 2 of 20 | The Iron Dome defense system, March 13, 2012. Credit: Nir Kafri

Earlier on Sunday, security officials said the Iron Dome systems performed extraordinarily. The systems use a missile called "Tamir" to intercept incoming rockets, with each missile priced at approximately NIS 200,000.

Also on Sunday, Defense Minister Ehud Barak said he intends to define the multi-level antimissile interception system as a national security project. Barak is demanding faster deployment of additional Iron Dome systems and the completion and deployment of the "Magic Wand" system, which is designed to intercept long-range rockets.

School was called off on Sunday in Ashkelon, Be'er Sheva, Ashdod and other regional councils in Israel south, affecting some 207,000 students. On Monday, classes will be cancelled in towns located within 40 kilometers of the Gaza Strip.

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