Powerful explosion kills 4 Palestinians in Gaza. Israel says the blast was caused by mishandled bomb

GAZA CITY, Gaza Strip (AP) — Palestinian health officials in the Gaza Strip say at least four people have been killed and 20 others wounded in an explosion next to the separation fence along the Israeli frontier with Gaza. The cause of Wednesday’s blast wasn’t immediately known. The explosion took place during a demonstration along the fence marking the anniversary of Israel’s withdrawal from the Gaza Strip in 2005. The event was organized by Hamas. The Islamic militant group has governed the territory since 2007. The Israeli army denied involvement. It says demonstrators were trying to throw a bomb over the fence when the device detonated.