Following a deadly suicide attack on Thursday night and the continued Kassam bombardment of the western Negev, the IDF over the weekend stepped up its operations and pounded the Gaza Strip with missiles from aircraft and warships, while IDF troops sealed off Nablus from the rest of the West Bank. Following an escalation on the Gaza front, which included last week's launching of a Katyusha rocket at Israel, the IDF decided over the weekend to step up its strikes on Gaza and, employing artillery forces as well as the IAF and the Navy, fired around 200 shells at Kassam launch sites over the weekend. Early Saturday, IAF missiles flattened a building in the northern Gaza Strip that functioned as a hideout for terrorists and a launch site for Kassam cells. Under construction, the tall building was supposed to draw tourists and serve as a casino on the outskirts of Beit Hanun. But those plans were thwarted on Saturday after the Southern Command's Intelligence Department recently discovered ditches built around the building which were used to provide cover for Kassam launchers. On Friday, Abdel Karim Koka, a senior commander of the Salah-a-Din faction of the Popular Resistance Committees in the Gaza Strip, was killed when his car exploded in Gaza City. The army denied its involvement in the explosion but said that Koka was responsible for numerous Kassam attacks against Israel. In the past, IDF artillery fire against Kassam rocket cells targeted empty fields in the vicinity of the launch sites but not the precise position of the launchers. The bombings of the casino building and additional empty areas within Gaza City were meant to send a message, military sources said, to the newly formed Hamas-run Palestinian government that they would suffer if they failed to rein in terrorism. The army also threatened to strike official Palestinian security personnel whose posts were often used as cover for Kassam launch cells. "We cannot promise that PA police will not be hurt during the strikes," one source said. The army also engaged in psychological warfare and dropped thousands of flyers over the Gaza Strip calling on the Palestinian public to expel terror elements from within. "How long will you let terrorists control your lives?" the fliers asked, warning that Israel's military response would grow harsher as long as Kassam fire continued. But despite the massive bombardment on Gaza, Kassam rocket fire continued. On Saturday night four rockets were launched from the northern Gaza Strip, with at least two landing near Kibbutz Zikim south of Ashkelon. On Friday night three rockets were fired from Gaza, landing south of Sderot. Meanwhile Friday, Defense Minister Shaul Mofaz blamed the Hamas government for a suicide bombing a day earlier that killed four Israelis at the entrance to the Samarian settlement of Kedumim. "A government that engraves terrorism on its flag and does not order PA security forces to fight terror is accountable for this attack and every other attack that emerges from Palestinian territories," Mofaz said. Mofaz ordered the IDF and the Shin Bet (Israel Security Agency) to "intensify their operations" in the West Bank and Gaza in an effort to crack down on terror infrastructure there. In response to the suicide attack, the IDF on Saturday sealed off Nablus, deemed a "terror capital" by the IDF, and implemented a series of stringent regulations at nearby checkpoints. Palestinians between the ages of 16-32 were banned from traveling south of northern Samaria and checkpoints between Nablus and the Jordan Valley were closed off to Palestinian traffic. Thursday's attack, which was initially thought to be a terror "work accident" without Israeli casualties, turned out to be a suicide bombing carried out by 24-year-old Ahmad Mashrake, from the Hebron area, who, disguised as a Jew, hitched a ride with an Israeli couple and detonated a bomb inside the car. Four people were killed in the attack: Rafi and Helena Halevy from Kedumim; Reut Feldman, 20, from Herzliya; and Shaked Laskar, 16, from Kedumim. The Fatah-affiliated Aksa Martyrs Brigades took responsibility for the attack and Shin Bet sources revealed that Mashrake had recently been released from a Palestinian prison. A spokesman for the terror group said Israel should prepare "a large amount of body bags" for terrorist attacks that his organization planned to execute. The attack was coordinated in conjunction with the Nablus-based Popular Front for the Liberation of Palestine, which provided the explosive device used in the attack. "All the organizations are working together," a military source explained. "Group affiliation is no longer relevant and with Iran and Syria sending money to the territories everyone, is trying to perpetrate terror attacks." Kedumim Regional Council head Daniella Weiss blamed Acting Prime Minister Ehud Olmert's convergence plan for the terror attack. "Olmert's delusional plan to give away land has motivated the Palestinians to try and push us out of our homes through acts of terror," she said. Benzi Lieberman, head of the Council of Judea, Samaria and Gaza (Yesha), urged Olmert to abandon his West Bank withdrawal plan and focus on ensuring the security of Israel's citizens. "This painful terror attack makes it very clear that Olmert needs to establish a government that will fight terror in Samaria and Gaza and will not just give in to the Palestinian demands and withdraw from the West Bank," a Yesha spokesman said.