Israel’s fiercest bombardment of the Gaza Strip for forty years has continued into its fourth day. At least 10 Palestinians died overnight as fighter jets targeted Hamas government buildings and security installations in the coastal enclave. Medical workers said those killed were mainly security guards and civilians. Its feared more people could be trapped in the rubble.Palestinian officials say the death toll from the onslaught has now risen to more than 340. The UN says at least 60 were civilians. In addition, more than 800 have been injured. UN Secretary General Ban Ki-moon has criticised both sides and called for an immediate ceasefire. The strikes began on Saturday, a week after the expiry of a six month-long ceasefire deal with Hamas, which has controlled Gaza since June 2007. Israel is massing tanks on the border with Gaza and has declared the zone a “closed area” for journalists, stoking rumours that a ground offensive is being prepared. With six weeks to go before an election that polls suggest the hawkish right-wing Likud Party may win, Israel’s centrist government says the onslaught is meant to put a stop to rocket fire from Hamas-linked militants.