Israeli forces and those of Islamic Jihad fired rockets at each other after a cease-fire was declared between the two sides, officials said. The cease-fire between Israel and the Islamic Jihad, negotiated by Egypt, went into effect 1 a.m. Tuesday following four days of rocket attacks on southern Israel, the Palestinian Ma\'an News Agency reported. Israel broke the truce Wednesday when it flew warplanes that shelled northern and southern Gaza Strip. Palestinians responded by firing four rockets at southern Israel. No group has claimed responsibility for any of the attacks. The leader of the Islamic Jihad, Ahmad al-Mudallal, said his group is committed to a cease-fire with Israel, but they would retaliate for attacks on Gaza, The Jerusalem Post reported. \"We don\'t trust the occupation but we trust our steadfastness and resistance. We cannot be quiet during any aggression on the Palestinian people,\" Mudallal said, adding, \"The resistance is ready to respond to any Israeli attacks.\"