"If required, we won't hesitate to embark on a military operation against Hamas," Foreign Minister Tzipi Livni said on Wednesday night. Speaking at a campaign rally at Kadima's Tel Aviv branch, Livni said that "when we speak about a truce, it must be clear that it is from both sides, because if a Kassam lands, none of us is going to look to see who fired it. We will hold one group accountable, and that group is called Hamas," which, she said, was "responsible for everything that goes on in Gaza." Livni went on to say that "calm in exchange for calm" is not enough. "In my opinion, quiet that is used for regrouping, rearming and smuggling weapons into the Gaza Strip is not a positive quiet." The foreign minister stressed that the cease-fire must ultimately lead to the release of captured IDF soldier Gilad Schalit. "If Hamas wants something else that is important to it, like the Rafah border crossing, then they must remember, first and foremost, that there is something we hold very dear - Gilad Schalit." Similarly, Prime Minister Ehud Olmert said earlier Wednesday that he hoped the Gaza truce would hold, but that he was instructing the IDF to plan for military operations if it doesn't. "I hope it will succeed," he said, adding that "the Security Cabinet has instructed the defense minister and the military to prepare quickly for any operation that might be necessary." In his address to a philanthropy conference in Beit Yehoshua, Olmert alternated between hope for calm and warnings to Hamas. "Hamas is the address in Gaza, and it carries responsibility for everything that happens in Gaza," he said, indicating Israel would hit back at the group if there are truce violations by any of the various Gaza factions. Overall, Olmert said, nothing has changed. "We should not have illusions," he said. "The terror organizations, and Hamas among them, have not changed their goals ... to hit innocent Israeli civilians." But he added, "I believe there will be quiet in the South. I send my warmest regards to the residents of the South who faced long months (of attacks) and stood up to them."