Israeli troops and Hamas fighters fought fierce battles in the streets of Gaza's main city on Tuesday as Israel's war on Hamas entered its 18th day and the death toll spiralled above 900. The most relentless battles of the offensive erupted when Israeli special forces backed by tanks and air strikes lunged ever deeper into several neighbourhoods in the south in the early morning hours, witnesses said. Palestinian fighters fired back with roadside bombs, mortars and anti-tank rockets. Explosions, tank shell thuds and the rattle of gunfire kept terrified residents who had not yet fled the area awake all through the night.