The guns of Operation Blue Skies continued to pound the northern Gaza Strip with a pre-dawn attack Thursday, targeting six Kassam rocket launch sites. Since Wednesday evening, the IDF has used drones, spotters and artillery batteries to keep Palestinians out of the newly created buffer zone. But according to Col. (res.) Eran Duvdevani, a fellow at the International Policy Institute for Counter-Terrorism at the Interdisciplinary Center in Herzliya, the next step in Israel's war in defense of its southern towns is to send elite infantry units back into Gaza for nighttime ambushes. "It's a more cost-effective way of dealing with the problem than artillery," he said. Duvdevani said artillery batteries took too long react to field intelligence, while Palestinians could hear helicopters flying in and make their escape. A silent ambush would have a devastating psychological effects on those who entered the no-go zone, he said. For now, the government has ruled out introducing ground troops - the idea sounding too much like a replay of the security zone in southern Lebanon, which collapsed with a hasty withdrawal in June 2000. "It sounds like someone is looking for a new swamp to get stuck in," said Orit Dagani, who was an activist with Four Mothers, a group that pushed for a unilateral withdrawal from Lebanon. Duvdevani thinks the analogy is not accurate. "The security zone in Lebanon was done all wrong," he said. "We relied on fixed posts with logistical needs." Units can instead be rotated in for periods up to 72 hours, he added. It is an idea that the army is not yet ready to adopt. "We have a variety of ways - tanks, artillery, jets and snipers - of dealing with infiltrators," said a senior military source. "For now, we will make due with directing fire into the zone instead of sending in troops." Since Monday, Palestinians have fired 10 Kassams at Israel, prompting the IDF to create the no-go zone in northern Gaza Wednesday evening. The zone keeps Ashkelon out of rocket range, though towns closer to the border remain vulnerable. Before the start of Operation Blue Skies, IDF liaison officers warned Palestinian Authority security personnel and the army also distributed leaflets to Gaza residents telling them to keep out of the zone. Still, the military source said, the army would only fire on Palestinian combatants. PA Chairman Mahmoud Abbas condemned the creation of the no-go zone, saying: "Israel has left the Gaza Strip and has no right to come back. They should not make any pretext."