Two IDF soldiers were moderately wounded and 11 others were lightly wounded Saturday morning at the Kerem Shalom crossing in the southern Gaza Strip, when Hamas gunmen initiated a coordinated attack on the Israeli side of the crossing, which included heavy gunfire, mortar shell barrages and two car bombs. The attack began close to 7 a.m. when two vehicles arrived at the crossing under the cover of heavy fog and one of them detonated near army forces, wounding the 13 soldiers. The second booby-trapped car was spotted by troops after the initial explosion and did not go off, the army said. Immediately afterwards, an armored car - which may have once belonged to Fatah security forces - arrived at the scene, and its occupants began firing at the soldiers, backed by heavy mortar shell barrages. Four gunmen, including the driver of the car bomb, were believed to have been killed in the explosion and the exchanges of fire that ensued. Forces then entered Gaza in order to search for remaining members of the cell. The wounded soldiers were evacuated to Soroka Medical Center in Beersheba. Meanwhile, another armored vehicle was identified approaching the Kissufim crossing, north of Kerem Shalom. An IDF tank fired at the vehicle and hit it, apparently preventing a second attack. Throughout the events, residents of Israeli communities in the surrounding area were instructed to remain in their homes due to fears of terrorist infiltration. A few hours later, a mechanic with Hamas's police force was killed and four people were wounded in an IAF air strike in southern Gaza, Palestinian security and health officials said. The IDF said a suspicious vehicle was hit between Kerem Shalom and Gaza's Rafah crossing with Egypt. Witnesses said the target of the strike was a jeep parked near the Rafah crossing. Defense officials have said the attack was probably the result of months of planning, and its perpeterators probably aimed to kill as many soldiers as possible as well as abduct others. The soldiers' readiness and quick response prevented a much deadlier attack on the eve of Pessah, they said. "This is an escalation that could be dangerous if we do not stop it," a high-ranking official told Channel 10 News after the attack. "In this case, the incident ended with a relatively low number of casualties, compared to what [Hamas] had planned, but it should raise a red flag over our operations in the area." He added that the IDF "must investigate how the gunmen managed to gather so much intelligence [in preparation for the attack] without the IDF knowing about it." In Gaza City, a Hamas leader, Sami Abu Zuhri, said Hamas would carry out more attacks on crossings to break the nearly yearlong blockade of the territory. "These operations are the beginning of the explosions that Hamas has warned of," said Abu Zuhri. "If the parties don't intervene quickly to save Gaza and break the siege, what is coming will be greater." Hamas later released a farewell video of four attackers. The video showed the three vehicles Hamas said were used in the attack. One was an armored personnel carrier, the second resembled an IDF jeep and the third was a small sedan. The video showed the three vehicles driving off into the morning fog. The assailants posed for the camera, smiling and toting rifles. Hamas also organized two protests by women and children near two other Gaza crossings: the Erez crossing for passengers and the Karni cargo crossing. Near Erez, scores of women and children marched toward the terminal but stopped about a kilometer away. They burned tires and raised Hamas flags, then dispersed.