Eighteen ambulances, flanked by Palestinian police cars, began the slow procession from hospital morgues in northern Gaza to the cemetery where 18 victims of an Israeli artillery attack were to be buried today.

Hamas' supreme leader today called off a ceasefire with Israel and militants threatened to attack Americans after 18 members of a family, including eight children, were killed in an Israeli artillery barrage on a densely populated neighbourhood.

Israeli tank shells ripped through a residential neighbourhood in the northern Gaza Strip early today, killing at least 18 members of an extended family, including 10 children, as they slept, health officials said.