Israel’s military assault on Gaza is coming under increasing international scrutiny after 15 people, mostly women and children, were killed at a UN run school on Thursday.

200 others who had sought refuge were also injured in the strike, some severely.

Reports claim the shelter in Beit Hanoun had been hit by an Israeli tank shell.

The UN’s Secretary-General Ban Ki-Moon condemned the attack.

“I was shocked and appalled by what has happened in the Beit Hanoun UN school. It is totally unacceptable. I have condemned strongly. I’m telling to the parties — both Israelis and Hamas, Palestinians — that it’s morally wrong to kill your own people,” Ban said.

Despite a warning by Israel’s army to leave the school, the shelter was hit before anyone could.

The UN says it is the fourth time in four days that one of its schools in Gaza has been hit.

Among the dead was a mother and her one-year-old baby.

Israel, however, insisted it does not target civilians.

Israel’s Foreign Ministry Spokesman Yigal Palmor said: “Why is this fighting going on and why do we see the pictures that we see? I think there is a simple explanation that was provided by the EU foreign ministers in their statement a couple of days ago. Hamas is using its own civilians, Palestinian civilians as human shields.”

Tens of thousands of Palestinians have fled and been displaced by the fighting in Gaza, many seeking shelter in UN run buildings.

Despite that, Israel shows no signs of ending its 18 day offensive anytime soon. On Friday, it deployed tanks and troops closer to the Gaza border.