The fragile ceasefire in the trouble-torn Gaza Strip has come under severe strain today with deaths on both sides of the Middle East conflict.Israel’s military says a bomb was detonated against its forces on the Israeli side of the border fence near the Kissufim crossing. One soldier died. Three others were injured. In clashes that followed, a Palestinian man was killed. And Israel’s response has gone further. Tough talk from Defence Minister Ehud Barack, 10 days after Israel halted its devastating offensive that killed 1,300 people, was followed by an Israeli air strike. It injured a Hamas activist and at least one other person in southern Gaza. There have been Israeli incursions and Israel has shut down crossing points through which humanitarian aid enters the territory.