CAIRO (AFP) - Israeli Foreign Minister Tzipi Livni vowed on Thursday to strike back at the Hamas rulers of Gaza after a sharp escalation of violence in the Palestinian territory dashed hopes of a new truce. "Enough is enough. The situation is going to change," Livni said in Cairo after meeting Egyptian President Hosni Mubarak to discuss the deteriorating situation in the Gaza Strip since a truce expired six days ago. "Unfortunately there is one address to the situation of the people in the Gaza Strip, this is Hamas, Hamas controls them, Hamas decided to target Israel, this is something that has to be stopped and this is what we're going to do," she said in English. "Yesterday's escalation was unbearable," Livni said after Gaza fighters hit Israel with their biggest rocket barrage in six months to avenge the killing of three fighters from the movement. "Hamas needs to understand that our aspiration for peace does not mean that Israel will take this situation any longer," Livni said at a press conference with Egyptian Foreign Minister Ahmed Abul Gheit. "Hamas's control of the Gaza Strip is not only Israel's problem... but what we are doing is an expression of the needs of the region." "The situation in the Gaza Strip has become an obstacle on the way of the Palestinians toward a state," added Livni, who has vowed to topple Hamas if her Kadima party wins a general election in February. Livni has been heading the Israeli negotiating team in peace talks with the Palestinians that resumed in November last year but have failed to make any visible headway since. "Egypt has made clear that there should be restraint and no escalation and an alleviation of the humanitarian situation," he said, saying Israel should refrain from "collective punishment." He said Egypt would continue its mediation efforts, but expressed pessimism that a new truce could be achieved. "Egypt won't stop its efforts as long as the parties agree. But I do not imagine that we can convince both parties to return to the truce as long as there is such a strong confrontation between them." Israel's Maariv newspaper said the security cabinet had given the army the go-ahead to conduct expanded operations in Gaza after a meeting on Wednesday and Defence Minister Ehud Barak warned that Israel would respond to the fire. "Hamas... will pay a big price," he said. "We will not allow this situation to last." A UN statement said UN chief Ban Ki-moon was "gravely concerned" about the situation, that he condemned the rocket attacks and also called for an urgent easing of humanitarian conditions in the Gaza Strip. Israel's outgoing Prime Minister Ehud Olmert, meanwhile, called in an interview published on Thursday for residents of Gaza to stop Hamas from firing missiles into Israel. "I say to you in a last-minute call, stop it," Olmert said in an interview with the Arab television station Al-Arabiya, according to quotes reprinted in the Israeli media.