Two Israelis were killed when at least four Palestinian terrorists infiltrated the Nahal Oz fuel terminal from the Gaza Strip on Wednesday. Oleg Lipson, 37 and Lev Cherniak, 53, both residents of Beersheba, were employed at the terminal, which supplies the Gaza Strip with most of its fuel. IDF troops and emergency medical teams, who arrived on the scene, came under heavy gun and mortar fire. Two of the terrorists were killed by the IDF in the terminal, and at least two others fled back to the Gaza Strip. In a swift response, the military dispatched aircraft which hit a car carrying at least one of the terrorists. According to a Hamas spokesman, the man was seriously injured. The army said two of the attackers were killed in the strike. The army said that the terrorists' objective was probably to kidnap Israelis to Gaza and use them as a bargaining chip. Military sources said that the terrorists had cut the fence and entered Israel, and added that there were no signs of a tunnel near the site of the attack. In recent days, Hamas has threatened several times that it would breach the border. The army raised the level of alertness to level three, the highest level, throughout the Negev. Three terror groups, Islamic Jihad, the Popular Resistance Committees and Fatah's Mujahideen Brigades, claimed responsibility for the attack. Mortar shells were still being fired at Israeli communities in the area several hours after the attack. Government spokesman Mark Regev said Gaza's Hamas rulers are "responsible and will be held accountable."