Prime Minister Ehud Olmert said Wednesday he hopes the Gaza truce will hold, but he's instructing his army to plan for military operations if it doesn't. The truce was negotiated by Egypt, mediating between Israel and the Islamic Hamas rulers of Gaza. It goes into effect early Thursday. Olmert made his first public comment about the truce in a speech on Wednesday. He said, "I hope it will succeed." But added, "The Security Cabinet has instructed the defense minister and the military to prepare quickly for any operation that might be necessary" if the truce effort does not succeed. The truce is designed to end daily Palestinian rocket attacks on Israel and deadly Israeli reprisal raids. Also, Israel is expected to ease its blockade on Gaza. In his address to a philanthropy conference, 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 Islamic group if there are truce violations by any of the various militant groups. 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 Israel's) south. I send my warmest regards to the residents of the south who faced long months (of attacks) and stood up to them."