Three of those killed and the majority of the wounded in the late afternoon explosion at a house east of Gaza City were under the age of 16, said Gaza Health Ministry spokesman Adham Abu Salmia.
Hamas police said Israeli tank fire had hit the house.
The Israeli military alleged Palestinian fighters had launched mortars against Israeli troops Tuesday and the military shot at the source of the firing.
“Regrettably non-combatants were hurt, this is because the Hamas attacks from civilian areas,” the military said in a statement.
Israel hit a series of Palestinian fighter targets in the Gaza Strip earlier Tuesday, damaging smuggling tunnels and suspected weapons sites. Palestinian officials said 19 people were wounded in those attacks. Palestinians bombarded Israel with dozens of mortars on Saturday in the largest barrage in years.
The area between Gaza City and the Israeli border is the frequent site of violence between Palestinian militants and Israeli forces.
Israel’s volatile border with Gaza has been largely quiet since an overwhelming Israeli military offensive two years ago. But Israeli officials say Gaza’s ruling Hamas group has recovered from the fighting, and the area has begun to heat up in recent weeks.
The Israeli attacks were in response to a barrage of 56 mortar shells and rockets fired by Gaza militants over the past week, the military said. The tunnels, it added, were meant for militants to infiltrate Israeli territory to attack civilians and soldiers.
A military statement vowed to “respond with determination” to any attempt to attack Israelis.
Abu Obeida, a Hamas spokesman, said Hamas had carried out the recent attacks in response to Israeli “aggression.” But he said the group remains committed to an informal cease-fire if Israel keeps things quiet.
“The enemy will pay the price if it continues its aggression and its crimes against our people in the Gaza Strip,” he said, adding: “The Palestinian factions will adhere to halting resistance actions if the Zionist enemy stops its aggression.”
