Tel Aviv // Israel attacked the Gaza Strip for a second day yesterday, warning it may step up the strikes that have already killed more than 280 people and injured 600 others in one of the Jewish state's most violent onslaughts against Palestinians in six decades of conflict. Israeli tanks were massed at different points along the Gaza border and the cabinet approved the mobilisation of 6,500 army reservists. Israel's air force, in an aerial operation described by Israeli media as the country's biggest since the 1967 war, dropped bombs and missiles on security installations, government buildings, a TV station and a mosque associated with the Islamic group Hamas, which rules the impoverished enclave. Of the Palestinians killed since the attacks started on Saturday morning, Gaza health officials estimated that at least 180 were members of Hamas's security forces. Officials said women and children were among the dead, but it was not clear how many civilians were killed. One of Hamas's main security and prison compounds in Gaza City - a major symbol of the group's power - was also bombed and television footage showed rescuers picking through the rubble and searching for bodies, as plumes of black smoke rose from burning buildings around them. Gaza streets appeared deserted yesterday as many Gazans remained in their homes for fear of getting caught in a strike; schools were shut and so were most shops, news agencies reported. Israel's assault began just a week after its shaky, six-month-old ceasefire with Hamas expired. The truce had begun unravelling in early November, when Israeli troops raided Gaza to destroy what the army claimed was a tunnel built by militants to kidnap Israeli soldiers. Since then, Gaza fighters have fired hundreds of rockets and mortars at southern Israeli communities. Israel has claimed that its response was restrained, launching some air strikes in recent weeks that killed several militants and keeping its crossings with Gaza shut - a blockade that aid groups said was worsening already dire humanitarian conditions in the territory. Yesterday the Israeli army said it had bombed more than 40 tunnels that connect Gaza with Egypt's Sinai desert. The tunnels are used to take weapons and supplies into Gaza from abroad. Ehud Olmert, Israel's outgoing prime minister, told his cabinet yesterday that the operation aimed "to restore normal life and quiet to residents of the south who for many years have suffered from unceasing rocket and mortar fire" by Gaza militants. Defence officials did not rule out expanding the aerial operation by invading Gaza with ground forces, and said thousands more military reservists may be called up to help in the attacks. Yet the Israeli foreign minister, Tzipi Livni, who hopes to become prime minister after a Feb 10 election, appeared to rule out a large-scale invasion to restore Israeli control of the blockaded territory, once dotted with Jewish settlements. "Our goal is not to reoccupy Gaza Strip," she said on NBC's Meet the Press programme. Asked on Fox News if Israel was out to topple Hamas, Ms Livni replied: "Not now." On Saturday, about 90 Israeli jet planes and combat helicopters struck at security compounds, training facilities and rocket-launching pads in Gaza. Major Gen Yoav Galant, the Israeli army commander in charge of southern Israel and Gaza, was quoted as saying that the military would try to "send Gaza decades into the past" in terms of weapon capabilities. Yesterday, Israel's army chief of staff told the cabinet that half of Hamas's rocket-launching sites have been destroyed in the bombardment. Some analysts said Israel may be rushing to complete its attacks in Gaza before international pressure from western governments forces it to stop. The United States voiced only lukewarm criticism of Israel's assault on Saturday, cautioning it only to avoid hurting innocent civilians and holding Hamas responsible for the end of the ceasefire and the renewal of violence. The Israeli campaign has drawn strong criticism across the Arab world, prompting demonstrations in capitals including Amman, Cairo, Damascus and Beirut. Palestinians in the Israeli-occupied West Bank staged protest marches and many businesses remained shuttered in a general strike, while hundreds of Israel's Arab citizens took to the streets in cities including Nazareth in condemnation of the onslaught. Hamas remained defiant, with its exiled leader in Damascus, Khaled Meshaal, calling on Palestinians to launch a new intifada against Israel. And a Hamas spokesman, Fawzi Barhoum, urged Palestinian groups to use "all available means, including martyrdom operations" - a reference to suicide bombings in Israel - to "protect the Palestinian people". Israel called for a state of emergency in communities that are within 20km of Gaza, shutting schools and advising residents there to stay in bomb shelters amid estimates that militants may fire up to 200 rockets and mortars a day on the area. Israel also expects Hamas to use the more sophisticated, longer-range projectiles in its arsenal that could target population centres as far as 40km from the Gaza border - about double the distance its typical short-range rockets reach. Gaza militants fired about 60 rockets at Israel on Saturday, killing one civilian, and they pelted dozens more rockets yesterday, with two striking near Ashdod, a southern Israeli port city 30km from Gaza. The operation is supported by an overwhelming majority of the Israeli public, especially the residents of rocket-hit communities who have pressured the government to take aggressive steps and halt the rocket fire. However, some commentators spoke out against the campaign. Gideon Levy of the left-wing Haaretz newspaper wrote that the operation was as "excessive" as Israel's actions were during the 2006 war in Lebanon, and warned that Hamas is likely to emerge strengthened from the attacks - just as the Lebanese Shiite group Hizbollah was strengthened following the 2006 war. Mr Levy described the Israeli army as a "hero against the weak", with its strikes aiming "at showing Israelis, Arabs and the entire world that the might of the neighbourhood bully hasn't been exhausted. When he goes nuts, no one can stop him." vbekker@thenational.ae With additional reporting by Agence France-Presse