Powerful explosion kills 5 Palestinians in Gaza. Israel says the blast was caused by mishandled bomb

Gaza city (Gaza Strip): At least five Palestinians were killed and over 20 others were wounded on Wednesday in an explosion next to the separation fence along the Israeli frontier with Gaza, Palestinian health officials said.
The cause of the blast was not immediately known.
The explosion took place during a demonstration along the border marking the anniversary of Israel’s withdrawal from the Gaza Strip in 2005. The event on Gaza’s eastern border was organized by Hamas, the Islamic militant group that has governed the coastal territory since 2007.
The Israeli army, which has fought four wars with Hamas, denied involvement. It said demonstrators were trying to throw a bomb over the fence when the device detonated prematurely. It released aerial footage showing a blast along the fence. Debris flew into the air, and several people could be seen running away.
Protesters brandishing flags had been burning tires along the separation fence to celebrate the anniversary of Israel’s withdrawal. Suhail al-Hindi, a Hamas leader, praised the end of what he described as the “cruel Israeli occupation”.
The demonstration turned violent before the deadly blast. The army said demonstrators threw grenades and other explosives across the border, while soldiers responded with tear gas. Several of the 25 people wounded remain in serious condition.
Hamas seized control of Gaza from the internationally recognized Palestinian Authority in 2007, a year after winning parliamentary elections.
Israel and Egypt have maintained a crippling blockade on the territory since the Hamas takeover, in a measure that Israel says is needed to keep Hamas from arming. The blockade, which restricts movement of goods and people in and out of Gaza, has ravaged the local economy.