Israeli tanks and infantry fought battles with Hamas forces as soon as they crossed into Gaza Saturday evening, and both sides claimed taking several lives. The ground incursion did not immediately stop Hamas rocket-fire into Israel Emergency services said a Palestinian child was among the early fatal victims with 11 others wounded when a tank shell hit a house in eastern Gaza City, taking the Palestinian death toll since Dec. 27 to nearly 470. Shortly after Israeli troops poured into northern Gaza from four entry points to end rocket and mortar attacks by Hamas and its allies, the Israeli air force bombed a gas depot near Beit Lahiya in northern Gaza causing a huge explosion, witnesses said. The blast cut cooking gas supply to the local population. Israel said the operation in the Hamas-run enclave could take “many long days.” Hamas official Ismail Radwan, said in a message to Israeli soldiers: “Gaza will be a graveyard for you.” Hamas is believed to have about 25,000 fighters and has placed landmines and other traps in anticipation of the invasion. Large numbers of Israeli forces were involved in the sweep, including infantry, tanks, engineers, artillery and intelligence, the military said in a statement. “The objective is to destroy the Hamas terror infrastructure in the area of operations,” Major Avital Leibovich said. The 2006 lesson Experts said the ground offensive will meet stiff resistance and guerilla tactics that will exact a heavy toll on both sides. “Dozens of Israeli troops could be killed in a ground operation. The number of Palestinian fatalities could be three or four times bigger,” said Efraim Inbar, the director of the Begin-Saadat center at Bar Ilan university. The challenge the Israeli army faces in Gaza has been overshadowed by the 2006 war against the Shiite Hezbollah militia in Lebanon, when the military struggled against a well-trained and dug-in guerilla forces. A spokesman for Hamas's armed wing, the Izz el-Deen Al-Qassam Brigades, said Israeli troops faced certain death or capture. “The Zionist enemy must know his battle in Gaza is a losing one,” said the spokesman, Abu Ubaida. Four Israelis were killed by rockets that continued to pound southern Israel after the ground forces moved across the frontier. Israeli Defense Minister Ehud Barak, in a television address said the ground push was to “protect the home front” from rocket attacks. “It won't be easy. It won't be short. I don't want to delude anyone,” said Barak, leader of the center-left Labor party, and a candidate for prime minister in an election that opinion polls predict will return right-winger Benjamin Netanyahu to power. Blatant US support The US State Department, while urging the Israeli military to be mindful of potential civilian consequences, said any ceasefire in Gaza must not allow a return to the status quo. “We are working toward a ceasefire that would not allow a reestablishment of the status quo ante, where Hamas can continue to launch rockets out of Gaza and to condemn the people of Gaza to a life of misery,” said spokesman Sean McCormack. The Czech EU Presidency spokesman Jiri Potuznik alsoopenly backed Israel: “At the moment, from the perspective of the last days, we understand this step as a defensive, not offensive, action.” Former British prime minister Tony Blair, representing major powers sponsoring Middle East peace talks, planned to begin shuttling on Sunday between Israeli leaders in occupied Jerusalem and Palestinian leaders in the occupied West Bank. But divisions within the European Union over the Israeli operation could reduce pressure on Israel to cease fire. Blair does not plan to meet Hamas, which opposes the statehood negotiations. On Monday, French President Nicolas Sarkozy is scheduled to go to occupied Jerusalem. Hours before the advance, an Israeli air strike killed 11 Palestinian worshippers, including children, and wounded dozens at a mosque in Beit Lahiya, Hamas officials and medics said. The plight of the 1.5 million Palestinians crammed into Gaza was growing more desperate. People have taken shelter in their homes for days and aid agencies warned that food, water and medical supplies were running short. Heavy casualties are likely to increase international pressure on Israel to halt its biggest operation in the Gaza Strip in four decades, fighting that holds significant political risks for Israeli leaders ahead of a Feb. 10 national election. At least a quarter of the 449 Palestinians killed in the current conflict have been civilians, a UN agency said. Another 2,050 Palestinians have been wounded. __