IDF special forces operated deep inside the Gaza Strip late Monday night in the first ground operation there since last summer's disengagement, killing four Islamic Jihad members on their way to fire Kassam rockets. Operating on precise intelligence, the troops laid an ambush in the northern Gaza village of Beit Lahiya. Backed up by IAF helicopter fire, they opened fire at a terror cell they spotted on its way to launch Kassam rockets. Four Palestinians were killed and eight were wounded during the clash, which lasted close to five hours and ended just before dawn. The troops penetrated about three kilometers into the Strip, marking a major shift in the way the army has operated since its withdrawal from Gaza. Until now, the IDF has combated Kassam rocket fire from outside Gaza, utilizing artillery and air strikes. Before Monday's raid, soldiers had only entered a few meters into Gaza, searching for mines along the border fence, but avoided operations deep inside the Strip. Defense Minister Amir Peretz praised the unit that conducted the raid, adding that the IDF would continue operating on the ground within the Gaza Strip and would take all necessary measures to prevent Kassam fire. He told the cabinet on Tuesday that the Shin Bet (Israel Security Agency) had recorded 10 concrete terror threats and more than 80 general terror alerts. Late Monday night, a mortar shell landed near an IDF base outside Kibbutz Nahal Oz in the Negev. Kassam rockets and other shells landed in open fields in the western Negev. The Gaza raid, senior IDF officers said, did not signify a shift in policy or indicate plans to invade the Strip in a massive ground operation. "We will use all of our available resources to destroy terror infrastructure in the Gaza Strip," one officer said. "We utilize a variety of resources, including air strikes, artillery fire and ground ambushes." Meanwhile, in early morning raids on Tuesday, troops shot and killed two terrorists in separate incidents in the Kabatiya refugee camp near Jenin and the Balata refugee camp near Nablus. Troops searching for fugitives in Balata spotted an armed man, whom they fired upon and killed. He was identified by Palestinian sources as a 17-year-old member of the Aksa Martyrs Brigades. In Kabatiya, an Islamic Jihad operative was killed after he opened fire on troops conducting arrest raids. Four other Islamic Jihad operatives were wounded, and the IDF said that the group had been planning a terror attack in an Israeli city. On Monday, IDF troops near Nablus thwarted a suicide bombing in Jerusalem after they caught two men carrying an explosives-filled vest trying to infiltrate into Israel from the West Bank. Also Monday, troops shot dead an Egyptian who tried to infiltrate into Israel. A military force patrolling the border spotted six men trying to cross into Israel. The soldiers called on the men to stop and, when they failed to heed the calls, opened fire. Five of the infiltrators fled back into Egypt.