(adds quote, background) ROME, Nov 8 (Reuters) - Italy's foreign minister branded the killing on Wednesday of 18 civilians in northern Gaza by Israeli artillery shells a "massacre" and called for an urgent international initiative to stop the violence. "This morning 18 people, women and children, were massacred ... an escalation of violence I think is unacceptable," Foreign Minister Massimo D'Alema told reporters. "I think that now an international initiative to unblock the Palestinian situation is essential." Shells killed 18 civilians in Beit Hanoun, a town in the northern Gaza Strip that has been the focus of an Israeli campaign against militants firing rockets into Israel. Thirteen members of one extended family were killed and the dead included seven children and four women, residents and the Palestinian Health Ministry said. It was the deadliest strike in the territory in four years. "It is clear that if this escalation of violence is not stopped we risk returning to a climate of war," D'Alema said.
