“Six Palestinians have been killed and others wounded in an explosion in the Gaza Strip, health officials say. It is not clear what caused the blast in Deir al-Balah. The Izzedine al-Qassam Brigades, military wing of the Hamas militant group, blamed Israel, but the Israeli military said it was not involved. A Palestinian source quoted by the Israeli newspaper Haaretz said that the victims appeared to be members of Hamas. The explosion could have been caused by the handling of explosives inside a building, the source added.”
Source: Gaza explosion leaves six Palestinians dead – BBC News