Four mortar shells fired by Gaza terrorists landed near the border fence Sunday evening. Police and the military initially thought the siren system malfunctioned when its sensors predicted four to eight incoming projectiles, as such a salvo of rockets has not been fired in months, but later realized that mortar shells, and not Kassam rockets as initially thought, were indeed launched. There were no casualties or damage, and police officers were searching for other shells which may have been launched. The IDF was skeptical when the sirens announcing the large salvo wailed, after a long period of relative calm in the South. But, a local security official said, a salvo of mortar shells was not out of the ordinary. Despite the relative calm, Gaza terrorists began increasing their activity lately, including efforts to booby-trap the security fence and infiltrate Israel. The IAF bombed a smuggling tunnel along the Gaza-Egypt border overnight Saturday, in retaliation for a Kassam rocket fired earlier Saturday morning.