GAZA CITY (Agencies) - Israel killed a top Hamas commander on Thursday in the biggest blow yet against the Islamist leadership as dozens more airstrikes on Gaza took the death toll from the six-day blitz to 423. With tanks and troops massed around the Palestinian enclave for a threatened ground offensive, Hamas sent more rockets deep into Israeli territory as Israeli warplanes and naval artillery staged more than 50 new attacks on Gaza. Two Israeli fighter jets swooped on the home of Nizar Rayan in the Jabaliya refugee camp, killing his four wives and 10 of his children, medics and witnesses said. Rayan, a hardliner within the Islamist group, was killed when a missile crashed into a five-storey house that he shared with his wives and 12 children in Jabaliya in the north of the territory, the medics said. Israeli warplanes also dropped a one-ton bomb on Rayan house. In addition to Rayan, his four wives and 10 children, another two people were killed, said Moawiya Hassanein, who heads Gaza's emergency services. The Israeli army said that it had targeted Rayan's house during a strike. Rayan's decapitated body was hurled into the street by the force of the blast which also destroyed 12 nearby houses. He was the most senior Hamas figure to be killed by Israel since Abdel Aziz al-Rantissi in 2004. The firebrand orator had lambasted Palestinian President Mahmud Abbas and called for suicide attacks on Israel during televised speeches and at rallies. "Operation Cast Lead" has now left 423 Palestinians dead and more than 2,100 wounded, according to Palestinian emergency services. Rockets fired from Gaza have killed four people and wounded dozens in Israel. The new Israeli strikes also hit the parliament and Justice Ministry in the main Hamas government complex, rocket launching sites, tunnels used to smuggle weapons and supplies into the territory and weapons storage facilities, a military spokeswoman said. Hundreds of houses have been destroyed and the United Nations says scores of the dead are civilians. Food, fuel and medical supplies are all running short, according to aid agencies. Israel has demanded the rocket fire by Hamas stop as a condition for a ceasefire but more than 40 were fired on Thursday, without causing new casualties, the military said. Speaking in Beersheva, Israeli Prime Minister Ehud Olmert said Israel is "not interested in conducting a long war" but insisted, "We will deal with Hamas and terror with an iron fist." Hamas' armed wing said it fired three rockets at the Hatzerim air force base west of Beersheva. The Israeli army did not comment. Hamas called on Palestinians in the occupied West Bank and annexed east Jerusalem to mark a "day of wrath" on Friday (today) by demonstrating against the Israeli offensive on the Gaza Strip. The Islamist movement called on its website for "massive marches" following the weekly Muslim prayers, starting off from the Al-Aqsa mosque compound in Jerusalem and from "all the mosques in the West Bank." A top Hamas official on Thursday denied saying the group had conditionally accepted an EU truce proposal for Gaza violence, saying a bogus statement had been published on the main Hamas website. "It is a false statement devoid of any truth," Hamas spokesman Fawzi Barhum told AFP. "It was disseminated by hostile parties in order to raise doubt as to Hamas positions. I have not made any statements on this topic." Earlier, the website carried a statement attributed to Barhum saying that the movement was accepting the EU truce proposal under certain conditions. "A ceasefire deal must be part of a global agreement including a ceasefire, the lifting of the blockade and the reopening of all the border crossings," the statement said. In a defiant televised speech late Wednesday, Hamas government chief Ismail Haniya vowed Israel would be defeated. "Our people will defeat those tanks," he said.