Israel hit the Gaza Strip with more air strikes on Tuesday and warned its military action could last weeks, while its Islamist enemy Hamas vowed to keep up rocket attacks on Israeli cities. Both sides rejected any notion of a ceasefire soon, three days after Israeli leaders launched bombing raids with the declared aim of halting rocket salvoes from the Hamas-controlled coastal enclave. Israeli warplanes pressed on for the fourth day with attacks on Hamas targets, killing 12 Palestinians. They included sisters aged 4 and 11. Several rockets fired from Gaza hit Israel, a day after three Israelis were killed in cross-border salvoes. Medical officials put Palestinian casualties since Saturday at 384 dead with more than 1,400 wounded. A United Nations agency said at least 62 of the dead were civilians. In all, four Israelis have been killed since the operation began. “We are living in horror, we and our children. The situation is not just bad, it is tragic,” said Gaza resident Abu Fares, standing outside his home, near the rubble of a building that was bombed and destroyed overnight. Mushir al-Masri, a Hamas official said “We are not begging for calm and there is no room to talk about calm amid the continued aggression and siege.” Hamas seized control of the Gaza Strip from Palestinian President Mahmoud Abbas's Fatah faction in fighting in June 2007. It has rejected international demands to recognize Israel, renounce violence and accept existing interim peace deals. “We are scared... that we can die at any moment,” said 11-year-old Mohammed Ayyad, still terrified hours after the strikes on Hamas government buildings next to his house in Gaza. Like the rest of Gaza's children, he has been traumatized by the four-day assault on Islamist Hamas targets which has transformed many areas into piles of rubble and shattered glass. Another boy, 12-year-old Nidal Bassal, said, “We're still scared. The Jews are crazy and they don't spare anyone, even children.” Meanwhile in Lebanon a boat carrying international peace activists and medical supplies to Gaza sailed into a Lebanese port, Tuesday - after being turned back and damaged by the Israeli navy, 90 miles off the coast of Gaza in international waters organizers of the trip said. Gaza targets In Beit Hanoun, in the northern Gaza Strip, two sisters were killed in a air raid as they were taking out the trash near their home, medical workers said. The area has been a launching ground for cross-border rocket attacks. Later a security man was killed in a strike on a headquarters in Khan Yunis and Israeli missiles flattened five ministerial buildings and a structure belonging to the Islamic University in Gaza City. A Hamas sports center and two training camps belonging to the group were also destroyed in the attacks, which plunged Gaza into a blackout as explosions echoed across the city. Israeli aircraft fired missiles at the home of a senior commander in Hamas's armed wing. He was not home. Another attack targeted offices belonging to the Popular Resistance Committees militant group. Most Gazans in the territory of 1.5 million people, one of the most densely populated on earth, have stayed home, in rooms away from windows that could shatter in blasts from air strikes on Hamas facilities. – AgenciesInternational Aid The international Red Cross said Tuesday it is preparing to fly 11 tons of medical supplies to Israel to help Gaza's over-stretched hospitals. “The situation is difficult but increasingly under control,” a spokesman for the Red Cross said. The World Health Organization said it is preparing to fly 50 surgical kits. The kits will contain enough supplies to treat 5,000 wounded people. It is also shipping nine basic health kits to Gaza - enough for three months' treatment of 90,000 people for common illnesses. China has pledged to send $1 million in aid to Gaza for “essential materials and supplies,” accoridng to a foreign ministry statement.