Gaza terrorists resumed their attacks on southern Israeli civilian areas on Monday night, firing a Kassam rocket that hit a kibbutz in the Sha'ar Hanegev region. No one was wounded and no damage was reported in the attack, and the rocket warning siren was sounded. Earlier Monday, minutes after a mortar shell struck an open area in the Eshkol region, IAF warplanes responded, launching a missile at a vehicle in the southern Gaza Strip. According to witnesses in the area, one person was killed and three others were wounded in the attack. The IDF said that the men were part of the cell which fired the mortar shell into Israel. Late Sunday night, IAF planes struck Hamas targets throughout Gaza after at least 15 Kassam rockets and mortar shells had hit the western Negev since the beginning of the day. There has been growing frustration in the political echelon at the increasing Palestinian truce violations. On Monday, Defense Minister Ehud Barak said that while Operation Cast Lead was effective in damaging Hamas's capability to threaten Israel, the day may come when a similar operation would be necessary. "The quiet in the South is a result of the serious blow dealt to Hamas in Gaza, and even if it takes a little more time and a few more shots are fired, this is the nature of events of this kind," Barak told Army Radio, but he added that "if we have to, we will hit Hamas again." The defense minister also said that Israel was interested in Egyptian cooperation in the battle to halt arms smuggling into Gaza through tunnels. Late Sunday evening, the IAF struck rocket-launching pads in northern Gaza, as well as a Hamas security building in central Gaza and six smuggling tunnels on the border. According to many Palestinians, Israel had sent them messages by phone, warning them in advance of an imminent IAF strike. There were no reports of casualties in the attack. Prime Minister Ehud Olmert promised a "harsh" and "disproportionate" response to the renewal of rocket fire into Israel when he addressed the cabinet on Sunday, shortly after a rocket landed near a kindergarten in the Eshkol region. "The cabinet's position from the outset was that if firing continues against residents of the South, there will be a sharp Israeli response that would be disproportionate vis-Ã¡-vis the firing," he said. The Palestinian Authority and Hamas leaders, meanwhile, were said to be close to reaching a Gaza cease-fire deal in talks with Egyptian officials in Cairo. Yaakov Katz, Tovah Lazaroff, and Brenda Gazzar contributed to this report.