"The data raise questions regarding the efficiency of any system," an official said.

On Wednesday, Palestinian gunners fired at least six Kassam-class missiles toward the Israeli city of Sderot. There were no reports of injuries in the attacks, in which Fatah claimed responsibility.

Officials said the Defense Ministry drafted scenarios that included Hizbullah and Palestinian rocket and missile attacks from the south and north. They said a key requirement of any missile defense system was that it protect an area of 10 square kilometers.

The report said a kinetic interceptor would be more successful than laser. The laser was said to be capable of protecting a smaller area than a kinetic interceptor.

In February 2007, Rafael, Israel Armament Development Authority was awarded the missile defense project with a comprehensive system designed to protect against short-, medium- and long-range rockets. Rafael's Iron Dome system was approved by Prime Minister Ehud Olmert and Defense Minister Amir Peretz.

"This was the most successful alternative in terms of the solutions it provides, the timetable for its development and costs," Olmert's office said in a statement on Feb. 4. "It was clearly necessary to develop and deploy this system, which along with other long- and intermediate-range defensive systems, would provide residents of Israel with optimal protection against missiles."

Still, former Rafael chief executive officer Zev Bonen said Iron Dome would be limited in capability. Bonen said no anti-rocket system could protect such cities as Sderot and Kiryat Shmona.

"The system that will be developed years from now will provide good, rather than absolute, protection to the interior part of the country but not the front, the focus of attacks and which the enemy seeks to exploit to spark a flight," Bonen said.