Four Kassam rockets landed Thursday morning, two in Israeli territory and two of them in Palestinian territories. Early Thursday morning, the Red early warning system traced a launch to the Western Negev area. The rocket landed near Sderot in an open field, while no wounded or damage were reported in both incidents. Defense Minister Amir Peretz said late Wednesday that there was a limit to the restraint Israel would show in the face of repeated Palestinian violations of the recent cease-fire. "We have no intention of gambling with our citizens' security," Peretz said. The cease-fire between Israel and the Palestinian terror groups in the Gaza Strip continued to crumble on Wednesday after at least seven Kassam rockets struck the western Negev. Senior defense officials said Wednesday that Israel's lack of response to Palestinian attacks could be perceived by the Palestinians as weakness, and urged the government to reconsider its current policy of restraint, Army Radio reported. Meanwhile, an explosion occurred near a group of Palestinian terrorists trying to launch rockets at Israel from the northern Gaza Strip on Wednesday, residents said, blaming an IAF air strike for the blast. None of the Palestinian operatives was injured, residents said. The IDF denied any involvement in the incident. Three Kassams landed just outside Sderot on Wednesday. No casualties were reported in any of the attacks. Islamic Jihad claimed responsibility for the Sderot attack, saying it was "just the beginning" of its revenge for the deaths of the two high-ranking operatives killed by the IDF earlier in the day. Troops, operating with an undercover Border Police unit, killed the two Palestinian operatives during an arrest raid in the West Bank village of Sila near Jenin. The two were identified as Zalah Hafed Mahmoud Zupata, 23, and Hussam Mahmoud Ibrahim Issah, 23, both high-ranking members of the Islamic Jihad. Kalashnikov assault rifles and an M-16 rifle and ammunition were found in their possession, an IDF spokesperson said. Palestinian security officials said an IDF force entered Sila and surrounded a house, waging a gunbattle with the operatives barricaded inside. The IDF said the two operatives had been involved in attempts to carry out terror attacks in Israel, and that troops had killed them during an attempted arrest operation. Two police dogs belonging to the Border Police force were also killed when they were sent into the house during the operation.