GAZA CITY (AFP) - Hamas activists pounded Israel with rocket and mortar fire on Wednesday and vowed more attacks as the Jewish state warned it would hit back, further dimming the chances of a renewed ceasefire. Yahi al-Shaaher, 23, from Hamas' armed wing the Ezzedine al-Qassam Brigades, was killed and four others were wounded when an Israeli helicopter fired three missiles near the southern town of Rafah, Palestinian emergency services and witnesses said, as violence escalated in and around the territory. Gunmen launched more than 70 projectiles, the largest barrage since before an Egyptian-brokered truce went into effect in and around the besieged Palestinian territory in June. The ceasefire expired five days ago. Hamas vowed to step up its attacks if the Israeli army responded with strikes against the impoverished territory. Israel "should know that any decision to attack the Gaza Strip will open the gates of hell and we will make you regret your stupidity with tears of blood," the group's armed wing al-Qassam Brigades said in a statement. "Israel's stupidity will push us to expand (operations) and put in our line of fire thousands of new Zionists to defend the Palestinian people," it said. Israel in turn warned that it would strike back. "Our position is clear - we will answer quiet with quiet," government spokesman Mark Regev told AFP. "But we will answer terrorist attacks with actions to protect our people." "So far Israel has demonstrated enormous restraint despite daily rocket barrages on our civilian populations," he said, adding that Hamas has "acted deliberately to torpedo the calm and to undermine the understandings reached through Egypt." The Israeli security cabinet met for five hours on Wednesday to discuss a response to the fire from Gaza, but Prime Minister Ehud Olmert imposed a blackout on the discussions. Wednesday's barrage did not cause injuries but sowed panic among Israelis living near the Gaza border less than two months before a snap general election called for February. Wednesday's barrage did not cause injuries but sowed panic among Israelis living near the Gaza border less than two months before a snap general election called for February. The military wing of Hamas said Wednesday's volley was "to avenge the killing" of three of its members by the Israeli army late on Tuesday. The army said it had fired at three activists planting explosives near the border fence. In response to the latest rocket fire, Israel said it would keep the territory sealed on Wednesday after initially planning to reopen crossings to allow in aid shipments. Aid groups have warned of a deteriorating humanitarian situation in the tiny overcrowded territory, which has been largely cut off from the outside world by Israel since Hamas violently seized power in June 2007. They have repeatedly appealed to Israel to ease its blockade and allow shipments into Gaza, where most of the 1.5 million population depends on foreign aid.