"We are talking about regular Iranian-made rockets," an official quoted the intelligence official as saying.

The 122-millimetre rockets have a range of about 20 kilometres (12.5 miles) and carry a large payload which caused heavy damage to buildings in the southern coastal town of Ashkelon, which bore the brunt of the Grad rocket fire.

Israel believes that over 100 such rockets were smuggled into the Hamas-ruled Gaza Strip through its porous border with Egypt in recent months following the Hamas violent takeover of the territory, a security official has told AFP.

Israel accuses Iran of actively backing and supplying arms to Hamas.