Twenty-three Kassam rockets pounded the western Negev on Wednesday as the IDF went on high alert ahead of the official end of the cease-fire on Friday. One of the rockets struck next to a shopping center in Sderot, wounding three people and causing extensive damage to storefronts and parked cars. The wounded were evacuated to Barzilai Medical Center in Ashkelon. Following the attack, the IDF bombed two rocket launchers in the northern Gaza Strip, next to Beit Hanun. The military said the launchers were ready for use. Moments later, two more Kassams hit the Sdot Negev region and another struck the Sha'ar Hanegev region. Defense officials said the escalation in rocket fire came after Hamas instructed Islamic Jihad to increase its attacks ahead of the end of the cease-fire. The officials predicted that Hamas would eventually agree to an extension of the truce but was "posturing itself" in an attempt to gain a commitment from Israel and Egypt to reopen the crossings into Gaza. In response to the ongoing violations of the cease-fire, Prime Minister Ehud Olmert warned of impending Israeli military action. "The rocket fire is just clarifying what we've been saying all along, that we can't have a situation where supposedly there is an agreed-upon cease-fire, while the reality on the ground is completely different," Olmert said after voting in the Kadima primary. "Of course this demands that we address the situation, and we will." Defense Minister Ehud Barak reiterated Wednesday night that Israel would not rush into an operation in Gaza. "We are not deterred from an operation in Gaza, but we are also not rushing into one," Barak said during a conference at the Institute for National Security Studies (INSS) in Tel Aviv. "When there is no choice, we will act when and where we see fit." Senior officers in the Gaza Division were harshly critical of the government's decision to prevent the IDF from responding to the rocket barrage. The officers said they saw the Kassams being launched but were not given permission to fire back. "We should respond," one officer said. "What is happening in Gaza in unimaginable, that the Palestinians continue to fire rockets and we are not allowed to enter Gaza to fight back." The IDF, officials said, was preparing for a number of scenarios, from small operations along the security fence to reconquering the entire Gaza Strip. Other scenarios include taking over the Philadelphi Corridor between Sinai and Gaza, where Hamas maintains tunnels - they are thought to number in the hundreds - that it uses to smuggle weapons and explosives into the Strip. Another IDF scenario calls for taking over the Kassam launch sites in northern Gaza. Each plan, the officials explained, has a different objective - stopping the smuggling, minimizing Kassam rocket fire and toppling the Hamas regime in Gaza. Under the leadership of OC Southern Command Maj.-Gen. Yoav Galant, each plan has already been approved by the General Staff and Barak. All the IDF needs is a green light. At the moment, the army has a number of units deployed along the border with Gaza. First, there is the Paratrooper's Brigade. It has been there since July and is scheduled to be replaced in the coming weeks by the Golani Brigade, which just completed four months of intensive training. There are also armored units, Engineering Corps teams and special forces. Ehud Barak warned Wednesday that if Iran acquires a nuclear weapon, it could try to attack the United States. At the INSS conference, Barak said the world should pressure Iran to stop it from building nuclear weapons. "If it built even a primitive nuclear weapon like the type that destroyed Hiroshima, Iran would not hesitate to load it on a ship, arm it with a detonator operated by GPS and sail it into a vital port on the east coast of North America," he said. Hinting at the possibility of a military strike, Barak said, "We are not taking any option off the table, and we recommend to the world not to take any option off the table, and we mean what we say."