Israel's military was facing questions on Wednesday as to whether its Iron Dome missile defence system needed an upgrade, after five Israeli civilians were killed by rocket strikes. The system, which Israeli officials say has a 90 per cent interception rate, has already avoided heavy loss of life in Tel Aviv, Ashkelon and other cities which became a focal point for Hamas as it sought to overwhelm air defences. But on Wednesday, Israeli analysts said that for some time intelligence sources had been warning that Hamas had significantly improved its weaponry, to the extent that it could "pierce the Iron Dome shield." “Iron Dome always had a weakness,” the Jerusalem Post’s intelligence, terrorism and legal analyst Yonah Jeremy Bob wrote in an article on Wednesday, referring to the system’s success rate. Mr Bob stressed that this did not mean that the Iron Dome was no longer effective.