Israel has launched deadly airstrikes in Gaza, in response to Palestinian rocket attacks. It is the worst flare-up in violence since Israel pulled out of the territory nearly two weeks ago.Palestinian militants fired rockets across the border after an explosion yesterday at a rally organised by Hamas killed 15 people. Prior to the blast, Israeli troops had killed three gunmen in a raid in the West Bank. Israel denied Hamas claims that it was responsible for the explosion in the Jabalya refugee camp. The Palestinian Authority said it appeared to be an accident, caused by Hamas members carrying explosives. As thousands marched in Gaza at the funerals of the victims, it was reported that at least two Hamas members were killed in the Israeli air strikes. Two other Palestinians also reportedly died. Earlier, five Israelis were wounded in the Palestinian rocket attacks at Sderot in Israel. Israeli forces have massed near the border with Gaza, with the defence minister promising what he calls a “crushing and unequivocal response”. The flare-up in violence is a blow to international hopes that Israel’s withdrawal from Gaza could revive peace efforts.