Chaos have been on the upswing in Gaza since Israel announced its intention to pull out of the poverty-stricken sea side terrutory next summer.
On Wednesday, Palestinian Premier Ahmed Qureia had said that his forces were unable to impose law and order.
A rocket attack that killed two Israeli toddlers on 29th September set off the Israeli invasion.
However on late Wednesday, Israeli aircraft targetted militants near Beit Lahiya, witnesses said, killing one Hamas member and wounding another.
Early on Thursday, another Hamas militant was killed in a missile strike in the Jebaliya camp, and a second died later in a hospital.
The Israeli military said in both cases, soldiers spotted militants planting explosives and targeted them in strikes.
Israeli helicopters fired missiles, killing three Palestinians, one of them a 70-year-old man. The military said it was a "routine" operation to remove cover for Palestinian gunmen.
Early on Thursday, Israeli troops moved out of the centre of Beit Lahiya, revealing that the army had razed large swaths of land, including hundreds of trees, during it's two-day occupation of the area.
Local residents returning to their homes also found houses damaged or demolished, roads torn up and water pipes damaged. The army did not immediately comment on the destruction.
